diff --git a/Alignment/CommonAlignmentAlgorithm/interface/AlignmentAlgorithmBase.h b/Alignment/CommonAlignmentAlgorithm/interface/AlignmentAlgorithmBase.h
index cd3da42563294..828e5024187b6 100644
--- a/Alignment/CommonAlignmentAlgorithm/interface/AlignmentAlgorithmBase.h
+++ b/Alignment/CommonAlignmentAlgorithm/interface/AlignmentAlgorithmBase.h
@@ -37,6 +37,7 @@ class Trajectory;
 #include "DataFormats/Alignment/interface/TkFittedLasBeamCollectionFwd.h"
 #include "DataFormats/Alignment/interface/AliClusterValueMapFwd.h"
 #include "DataFormats/TrackReco/interface/TrackFwd.h"
+#include "DataFormats/BeamSpot/interface/BeamSpotFwd.h"
 #include "FWCore/Framework/interface/Event.h"
 #include "FWCore/Framework/interface/ConsumesCollector.h"
 
@@ -44,9 +45,6 @@ namespace edm {
   class EventSetup;
   class ParameterSet;
 }  // namespace edm
-namespace reco {
-  class BeamSpot;
-}  // namespace reco
 
 /*** Global typedefs part I (see EOF for part II) ***/
 typedef std::pair<const Trajectory *, const reco::Track *> ConstTrajTrackPair;
diff --git a/Alignment/ReferenceTrajectories/interface/DualReferenceTrajectory.h b/Alignment/ReferenceTrajectories/interface/DualReferenceTrajectory.h
index 65d4bf4d7145f..7e1971d19b91c 100644
--- a/Alignment/ReferenceTrajectories/interface/DualReferenceTrajectory.h
+++ b/Alignment/ReferenceTrajectories/interface/DualReferenceTrajectory.h
@@ -28,11 +28,9 @@
 
 #include "Alignment/ReferenceTrajectories/interface/ReferenceTrajectoryBase.h"
 #include "DataFormats/TrajectorySeed/interface/PropagationDirection.h"
+#include "DataFormats/BeamSpot/interface/BeamSpotFwd.h"
 
 class ReferenceTrajectory;
-namespace reco {
-  class BeamSpot;
-}
 
 class DualReferenceTrajectory : public ReferenceTrajectoryBase {
 public:
diff --git a/Alignment/ReferenceTrajectories/interface/ReferenceTrajectory.h b/Alignment/ReferenceTrajectories/interface/ReferenceTrajectory.h
index 22339895b8429..9cda0d156669c 100644
--- a/Alignment/ReferenceTrajectories/interface/ReferenceTrajectory.h
+++ b/Alignment/ReferenceTrajectories/interface/ReferenceTrajectory.h
@@ -38,6 +38,7 @@
 #include "Alignment/ReferenceTrajectories/interface/ReferenceTrajectoryBase.h"
 #include "TrackingTools/TransientTrackingRecHit/interface/TransientTrackingRecHit.h"
 #include "DataFormats/TrajectorySeed/interface/PropagationDirection.h"
+#include "DataFormats/BeamSpot/interface/BeamSpotFwd.h"
 #include "TrackingTools/TrajectoryState/interface/SurfaceSideDefinition.h"
 
 #include "GblTrajectory.h"
@@ -48,10 +49,6 @@ class MaterialEffectsUpdator;
 class Plane;
 class BeamSpotTransientTrackingRecHit;
 
-namespace reco {
-  class BeamSpot;
-}
-
 class ReferenceTrajectory : public ReferenceTrajectoryBase {
 public:
   typedef SurfaceSideDefinition::SurfaceSide SurfaceSide;
diff --git a/Alignment/ReferenceTrajectories/interface/TrajectoryFactoryBase.h b/Alignment/ReferenceTrajectories/interface/TrajectoryFactoryBase.h
index 54ffd052b2aa5..d5d55019c9829 100644
--- a/Alignment/ReferenceTrajectories/interface/TrajectoryFactoryBase.h
+++ b/Alignment/ReferenceTrajectories/interface/TrajectoryFactoryBase.h
@@ -7,6 +7,7 @@
 #include "TrackingTools/PatternTools/interface/Trajectory.h"
 
 #include "DataFormats/TrajectorySeed/interface/PropagationDirection.h"
+#include "DataFormats/BeamSpot/interface/BeamSpotFwd.h"
 
 #include "FWCore/ParameterSet/interface/ParameterSet.h"
 
@@ -14,10 +15,6 @@
 /// Base class for factories producing reference trajectories, i.e. instances of classes deriving from
 /// ReferenceTrajectoryBase, from a TrajTrackPairCollection.
 
-namespace reco {
-  class BeamSpot;
-}
-
 class TrajectoryFactoryBase {
 public:
   typedef ReferenceTrajectoryBase::ReferenceTrajectoryPtr ReferenceTrajectoryPtr;
diff --git a/Alignment/ReferenceTrajectories/interface/TwoBodyDecayTrajectory.h b/Alignment/ReferenceTrajectories/interface/TwoBodyDecayTrajectory.h
index bdaa7966f8f24..6f8a761af7ffa 100644
--- a/Alignment/ReferenceTrajectories/interface/TwoBodyDecayTrajectory.h
+++ b/Alignment/ReferenceTrajectories/interface/TwoBodyDecayTrajectory.h
@@ -3,15 +3,12 @@
 
 #include "Alignment/ReferenceTrajectories/interface/ReferenceTrajectory.h"
 #include "Alignment/ReferenceTrajectories/interface/TwoBodyDecayTrajectoryState.h"
+#include "DataFormats/BeamSpot/interface/BeamSpotFwd.h"
 
 /**
    by Edmund Widl, see CMS NOTE-2007/032.
  */
 
-namespace reco {
-  class BeamSpot;
-}
-
 class TwoBodyDecayTrajectory : public ReferenceTrajectoryBase {
 public:
   typedef TransientTrackingRecHit::ConstRecHitContainer ConstRecHitContainer;
diff --git a/Alignment/ReferenceTrajectories/plugins/BzeroReferenceTrajectoryFactory.h b/Alignment/ReferenceTrajectories/plugins/BzeroReferenceTrajectoryFactory.h
index a64abf0260df4..ee55005799cbb 100644
--- a/Alignment/ReferenceTrajectories/plugins/BzeroReferenceTrajectoryFactory.h
+++ b/Alignment/ReferenceTrajectories/plugins/BzeroReferenceTrajectoryFactory.h
@@ -1,13 +1,11 @@
 #include "Alignment/ReferenceTrajectories/interface/TrajectoryFactoryBase.h"
 #include "MagneticField/Records/interface/IdealMagneticFieldRecord.h"
+#include "DataFormats/BeamSpot/interface/BeamSpotFwd.h"
 
 namespace edm {
   class ParameterSet;
   class EventSetup;
 }  // namespace edm
-namespace reco {
-  class BeamSpot;
-}
 
 /// A factory that produces instances of class BzeroReferenceTrajectory from a
 /// given TrajTrackPairCollection.
diff --git a/AnalysisDataFormats/TopObjects/interface/TtEventPartons.h b/AnalysisDataFormats/TopObjects/interface/TtEventPartons.h
index 9fac8b33c115c..dd571e6765c87 100644
--- a/AnalysisDataFormats/TopObjects/interface/TtEventPartons.h
+++ b/AnalysisDataFormats/TopObjects/interface/TtEventPartons.h
@@ -2,6 +2,7 @@
 #define TtEventPartons_h
 
 #include "DataFormats/HepMCCandidate/interface/GenParticle.h"
+#include "DataFormats/Candidate/interface/CandidateOnlyFwd.h"
 
 #include <vector>
 
@@ -11,9 +12,6 @@
    \brief   Common base class for TtFullLepEvtPartons, TtFullHadEvtPartons and TtSemiLepEvtPartons
 */
 
-namespace reco {
-  class Candidate;
-}
 class TtGenEvent;
 
 class TtEventPartons {
diff --git a/AnalysisDataFormats/TopObjects/interface/TtFullHadEvtPartons.h b/AnalysisDataFormats/TopObjects/interface/TtFullHadEvtPartons.h
index c991d7e25cdc5..b417734483c99 100644
--- a/AnalysisDataFormats/TopObjects/interface/TtFullHadEvtPartons.h
+++ b/AnalysisDataFormats/TopObjects/interface/TtFullHadEvtPartons.h
@@ -2,6 +2,7 @@
 #define TtFullHadEvtPartons_h
 
 #include "AnalysisDataFormats/TopObjects/interface/TtEventPartons.h"
+#include "DataFormats/Candidate/interface/CandidateOnlyFwd.h"
 
 #include <vector>
 
@@ -13,9 +14,6 @@
    This class is mainly used for the jet-parton matching in TopTools.
 */
 
-namespace reco {
-  class Candidate;
-}
 class TtGenEvent;
 
 class TtFullHadEvtPartons : public TtEventPartons {
diff --git a/AnalysisDataFormats/TopObjects/interface/TtFullLepEvtPartons.h b/AnalysisDataFormats/TopObjects/interface/TtFullLepEvtPartons.h
index 79ae67dc3cb2f..d7735a31a8bef 100644
--- a/AnalysisDataFormats/TopObjects/interface/TtFullLepEvtPartons.h
+++ b/AnalysisDataFormats/TopObjects/interface/TtFullLepEvtPartons.h
@@ -2,6 +2,7 @@
 #define TtFullLepEvtPartons_h
 
 #include "AnalysisDataFormats/TopObjects/interface/TtEventPartons.h"
+#include "DataFormats/Candidate/interface/CandidateOnlyFwd.h"
 
 #include <vector>
 
@@ -13,9 +14,6 @@
    This class is mainly used for the jet-parton matching in TopTools.
 */
 
-namespace reco {
-  class Candidate;
-}
 class TtGenEvent;
 
 class TtFullLepEvtPartons : public TtEventPartons {
diff --git a/AnalysisDataFormats/TopObjects/interface/TtSemiLepEvtPartons.h b/AnalysisDataFormats/TopObjects/interface/TtSemiLepEvtPartons.h
index cc39807080812..1df2467ecc3d5 100644
--- a/AnalysisDataFormats/TopObjects/interface/TtSemiLepEvtPartons.h
+++ b/AnalysisDataFormats/TopObjects/interface/TtSemiLepEvtPartons.h
@@ -2,6 +2,7 @@
 #define TtSemiLepEvtPartons_h
 
 #include "AnalysisDataFormats/TopObjects/interface/TtEventPartons.h"
+#include "DataFormats/Candidate/interface/CandidateOnlyFwd.h"
 
 #include <vector>
 
@@ -13,9 +14,6 @@
    This class is mainly used for the jet-parton matching in TopTools.
 */
 
-namespace reco {
-  class Candidate;
-}
 class TtGenEvent;
 
 class TtSemiLepEvtPartons : public TtEventPartons {
diff --git a/CommonTools/CandAlgos/interface/GenJetParticleSelector.h b/CommonTools/CandAlgos/interface/GenJetParticleSelector.h
index 3e67062e5079f..3527398ecf3d0 100644
--- a/CommonTools/CandAlgos/interface/GenJetParticleSelector.h
+++ b/CommonTools/CandAlgos/interface/GenJetParticleSelector.h
@@ -9,6 +9,7 @@
  */
 #include "SimGeneral/HepPDTRecord/interface/PdtEntry.h"
 #include "SimGeneral/HepPDTRecord/interface/ParticleDataTable.h"
+#include "DataFormats/Candidate/interface/CandidateOnlyFwd.h"
 #include "FWCore/Utilities/interface/ESGetToken.h"
 #include "FWCore/ParameterSet/interface/ParameterSetDescription.h"
 #include <set>
@@ -19,9 +20,6 @@ namespace edm {
   class Event;
   class ConsumesCollector;
 }  // namespace edm
-namespace reco {
-  class Candidate;
-}
 
 class GenJetParticleSelector {
 public:
diff --git a/CommonTools/CandUtils/interface/CandSelector.h b/CommonTools/CandUtils/interface/CandSelector.h
index 03ccac237b163..a870608b513a1 100644
--- a/CommonTools/CandUtils/interface/CandSelector.h
+++ b/CommonTools/CandUtils/interface/CandSelector.h
@@ -12,9 +12,7 @@
  *
  */
 
-namespace reco {
-  class Candidate;
-}
+#include "DataFormats/Candidate/interface/CandidateOnlyFwd.h"
 
 class CandSelector {
 public:
diff --git a/CommonTools/CandUtils/interface/zMCLeptonDaughters.h b/CommonTools/CandUtils/interface/zMCLeptonDaughters.h
index 03f97987992b0..f7517bdb05227 100644
--- a/CommonTools/CandUtils/interface/zMCLeptonDaughters.h
+++ b/CommonTools/CandUtils/interface/zMCLeptonDaughters.h
@@ -2,8 +2,9 @@
 #define CommonTools_CandUtils_zMCLeptonDaughters_h
 #include <utility>
 
+#include "DataFormats/Candidate/interface/CandidateOnlyFwd.h"
+
 namespace reco {
-  class Candidate;
   std::pair<const Candidate *, const Candidate *> zMCLeptonDaughters(const Candidate &z, int leptonPdgId);
 }  // namespace reco
 
diff --git a/DQM/Physics/src/EwkDQM.h b/DQM/Physics/src/EwkDQM.h
index dfbec2156dad6..87187d0647885 100644
--- a/DQM/Physics/src/EwkDQM.h
+++ b/DQM/Physics/src/EwkDQM.h
@@ -18,14 +18,11 @@
 #include "DataFormats/EgammaCandidates/interface/GsfElectronFwd.h"
 #include "DataFormats/MuonReco/interface/MuonFwd.h"
 #include "DataFormats/VertexReco/interface/VertexFwd.h"
+#include "DataFormats/METReco/interface/METFwd.h"
+#include "DataFormats/JetReco/interface/JetFwd.h"
 #include "DQMServices/Core/interface/DQMEDAnalyzer.h"
 #include "DQMServices/Core/interface/DQMStore.h"
 
-namespace reco {
-  class Jet;
-  class MET;
-}  // namespace reco
-
 class EwkDQM : public DQMEDAnalyzer {
 public:
   /// Constructor
diff --git a/DQM/Physics/src/EwkElecDQM.h b/DQM/Physics/src/EwkElecDQM.h
index 47ba9ef6c13b3..323fd832abb47 100644
--- a/DQM/Physics/src/EwkElecDQM.h
+++ b/DQM/Physics/src/EwkElecDQM.h
@@ -15,15 +15,12 @@
 
 #include "DataFormats/EgammaCandidates/interface/GsfElectronFwd.h"
 #include "DataFormats/VertexReco/interface/VertexFwd.h"
+#include "DataFormats/BeamSpot/interface/BeamSpotFwd.h"
+#include "DataFormats/METReco/interface/METFwd.h"
+#include "DataFormats/JetReco/interface/JetFwd.h"
 #include "DQMServices/Core/interface/DQMOneEDAnalyzer.h"
 #include "DQMServices/Core/interface/DQMStore.h"
 
-namespace reco {
-  class Jet;
-  class MET;
-  class BeamSpot;
-}  // namespace reco
-
 class EwkElecDQM : public DQMOneEDAnalyzer<> {
 public:
   EwkElecDQM(const edm::ParameterSet&);
diff --git a/DQM/Physics/src/EwkMuDQM.h b/DQM/Physics/src/EwkMuDQM.h
index 2e35ecc77bf65..44e50ca306cc8 100644
--- a/DQM/Physics/src/EwkMuDQM.h
+++ b/DQM/Physics/src/EwkMuDQM.h
@@ -11,19 +11,17 @@
 #include "FWCore/Framework/interface/MakerMacros.h"
 #include "HLTrigger/HLTcore/interface/HLTPrescaleProvider.h"
 
+#include "DataFormats/BeamSpot/interface/BeamSpotFwd.h"
+#include "DataFormats/METReco/interface/METFwd.h"
+#include "DataFormats/JetReco/interface/JetFwd.h"
+#include "DataFormats/MuonReco/interface/MuonFwd.h"
+#include "DataFormats/VertexReco/interface/VertexFwd.h"
+#include "DataFormats/EgammaCandidates/interface/PhotonFwd.h"
+
 #include "FWCore/Utilities/interface/InputTag.h"
 #include "DQMServices/Core/interface/DQMEDAnalyzer.h"
 #include "DQMServices/Core/interface/DQMStore.h"
 
-namespace reco {
-  class Muon;
-  class Jet;
-  class MET;
-  class Vertex;
-  class Photon;
-  class BeamSpot;
-}  // namespace reco
-
 class EwkMuDQM : public DQMEDAnalyzer {
 public:
   EwkMuDQM(const edm::ParameterSet&);
diff --git a/DQM/Physics/src/EwkMuLumiMonitorDQM.h b/DQM/Physics/src/EwkMuLumiMonitorDQM.h
index 0e5cba30ebce9..78e077153aa25 100644
--- a/DQM/Physics/src/EwkMuLumiMonitorDQM.h
+++ b/DQM/Physics/src/EwkMuLumiMonitorDQM.h
@@ -21,6 +21,8 @@
 #include "HLTrigger/HLTcore/interface/HLTConfigProvider.h"
 #include "DataFormats/MuonReco/interface/Muon.h"
 #include "DataFormats/TrackReco/interface/Track.h"
+#include "DataFormats/BeamSpot/interface/BeamSpotFwd.h"
+#include "DataFormats/METReco/interface/METFwd.h"
 #include "DataFormats/CaloTowers/interface/CaloTowerDefs.h"
 #include "DQMServices/Core/interface/DQMEDAnalyzer.h"
 #include "DQMServices/Core/interface/DQMStore.h"
@@ -28,10 +30,6 @@
 namespace trigger {
   class TriggerEvent;
 }
-namespace reco {
-  class BeamSpot;
-  class MET;
-}  // namespace reco
 
 class EwkMuLumiMonitorDQM : public DQMEDAnalyzer {
 public:
diff --git a/DQM/Physics/src/QcdPhotonsDQM.h b/DQM/Physics/src/QcdPhotonsDQM.h
index 8fba51f8ebc4b..aa271e87d7152 100644
--- a/DQM/Physics/src/QcdPhotonsDQM.h
+++ b/DQM/Physics/src/QcdPhotonsDQM.h
@@ -16,15 +16,12 @@
 #include "DataFormats/EcalRecHit/interface/EcalRecHitCollections.h"
 #include "DataFormats/EgammaCandidates/interface/PhotonFwd.h"
 #include "DataFormats/VertexReco/interface/VertexFwd.h"
+#include "DataFormats/JetReco/interface/JetFwd.h"
 #include "DQMServices/Core/interface/DQMEDAnalyzer.h"
 #include "DQMServices/Core/interface/DQMStore.h"
 
 #include "RecoEcal/EgammaCoreTools/interface/EcalClusterLazyTools.h"
 
-namespace reco {
-  class Jet;
-}
-
 class QcdPhotonsDQM : public DQMEDAnalyzer {
 public:
   /// Constructor
diff --git a/DQM/TrackingMonitor/interface/TrackAnalyzer.h b/DQM/TrackingMonitor/interface/TrackAnalyzer.h
index 13d8e61184808..2fc9593372e12 100644
--- a/DQM/TrackingMonitor/interface/TrackAnalyzer.h
+++ b/DQM/TrackingMonitor/interface/TrackAnalyzer.h
@@ -34,7 +34,6 @@ Monitoring source for general quantities related to tracks.
 #include "TrackingTools/TransientTrack/interface/TransientTrackBuilder.h"
 #include "TrackingTools/Records/interface/TransientTrackRecord.h"
 
-class BeamSpot;
 namespace tadqm {
   class TrackAnalyzer {
   public:
diff --git a/DQM/TrackingMonitorSource/interface/TrackToTrackComparisonHists.h b/DQM/TrackingMonitorSource/interface/TrackToTrackComparisonHists.h
index adfd142ce275d..e741e83d5c1e0 100644
--- a/DQM/TrackingMonitorSource/interface/TrackToTrackComparisonHists.h
+++ b/DQM/TrackingMonitorSource/interface/TrackToTrackComparisonHists.h
@@ -12,6 +12,7 @@
 #include "FWCore/Utilities/interface/EDGetToken.h"
 #include "DataFormats/TrackReco/interface/TrackFwd.h"
 #include "DataFormats/VertexReco/interface/VertexFwd.h"
+#include "DataFormats/BeamSpot/interface/BeamSpotFwd.h"
 #include "DataFormats/Scalers/interface/LumiScalers.h"
 #include "DataFormats/OnlineMetaData/interface/OnlineLuminosityRecord.h"
 #include "DQMServices/Core/interface/MonitorElement.h"
@@ -28,11 +29,6 @@
 // class declaration
 //
 class DQMStore;
-namespace reco {
-  class BeamSpot;
-  class Vertex;
-}  // namespace reco
-class DQMStore;
 class GenericTriggerEventFlag;
 
 class TrackToTrackComparisonHists : public DQMEDAnalyzer {
diff --git a/DataFormats/BeamSpot/interface/BeamSpotFwd.h b/DataFormats/BeamSpot/interface/BeamSpotFwd.h
new file mode 100644
index 0000000000000..de50e55009470
--- /dev/null
+++ b/DataFormats/BeamSpot/interface/BeamSpotFwd.h
@@ -0,0 +1,6 @@
+#ifndef DataFormats_BeamSpot_BeamSpotFwd_h
+#define DataFormats_BeamSpot_BeamSpotFwd_h
+namespace reco {
+  class BeamSpot;
+}
+#endif
diff --git a/DataFormats/BeamSpot/src/classes_def.xml b/DataFormats/BeamSpot/src/classes_def.xml
index e3fb016fa64ba..846be19d45b6b 100644
--- a/DataFormats/BeamSpot/src/classes_def.xml
+++ b/DataFormats/BeamSpot/src/classes_def.xml
@@ -5,7 +5,7 @@
   </class>
   <class name="edm::Wrapper<reco::BeamSpot>"/>
 
-  <class name="BeamSpotHost"/>
+  <class name="BeamSpotHost" rntupleStreamerMode="true"/>
   <!-- BeamSpotHost::Product must be listed before the aliased-to type -->
   <!-- TODO: we should find a better way than replicating the class versions and checksums -->
   <class name="BeamSpotHost::Product" ClassVersion="3">
diff --git a/DataFormats/Candidate/interface/CandidateOnlyFwd.h b/DataFormats/Candidate/interface/CandidateOnlyFwd.h
new file mode 100644
index 0000000000000..f5f3e09f1ca3a
--- /dev/null
+++ b/DataFormats/Candidate/interface/CandidateOnlyFwd.h
@@ -0,0 +1,6 @@
+#ifndef DataFormats_Candidate_CandidateOnlyFwd_h
+#define DataFormats_Candidate_CandidateOnlyFwd_h
+namespace reco {
+  class Candidate;
+}
+#endif
diff --git a/DataFormats/Candidate/interface/OverlapChecker.h b/DataFormats/Candidate/interface/OverlapChecker.h
index 8ce586af3805c..e051884d86a43 100644
--- a/DataFormats/Candidate/interface/OverlapChecker.h
+++ b/DataFormats/Candidate/interface/OverlapChecker.h
@@ -10,9 +10,7 @@
  *
  */
 
-namespace reco {
-  class Candidate;
-}
+#include "DataFormats/Candidate/interface/CandidateOnlyFwd.h"
 
 class OverlapChecker {
 public:
diff --git a/DataFormats/Candidate/interface/VertexCompositeCandidateOnlyFwd.h b/DataFormats/Candidate/interface/VertexCompositeCandidateOnlyFwd.h
new file mode 100644
index 0000000000000..9be4756e0a4fe
--- /dev/null
+++ b/DataFormats/Candidate/interface/VertexCompositeCandidateOnlyFwd.h
@@ -0,0 +1,6 @@
+#ifndef DataFormats_Candidate_VertexCompositeCandidateOnlyFwd_h
+#define DataFormats_Candidate_VertexCompositeCandidateOnlyFwd_h
+namespace reco {
+  class VertexCompositeCandidate;
+}
+#endif
diff --git a/DataFormats/Candidate/interface/component.h b/DataFormats/Candidate/interface/component.h
index 7a20f5c7f2531..9819a2b4c15a6 100644
--- a/DataFormats/Candidate/interface/component.h
+++ b/DataFormats/Candidate/interface/component.h
@@ -10,10 +10,9 @@
  */
 #include "FWCore/Utilities/interface/Exception.h"
 
+#include "DataFormats/Candidate/interface/CandidateOnlyFwd.h"
 namespace reco {
 
-  class Candidate;
-
   struct DefaultComponentTag {};
 
   namespace componenthelper {
diff --git a/DataFormats/EcalDigi/src/classes_def.xml b/DataFormats/EcalDigi/src/classes_def.xml
index e84ce6e755cb1..bbebb272d029a 100644
--- a/DataFormats/EcalDigi/src/classes_def.xml
+++ b/DataFormats/EcalDigi/src/classes_def.xml
@@ -152,9 +152,7 @@
    <class name="EcalDigiHostCollection::Layout"/>
    <class name="EcalDigiSoA"/>
    <class name="EcalDigiSoA::View"/>
-   <class name="EcalDigiHostCollection" ClassVersion="3">
-     <version ClassVersion="3" checksum="9207964"/>
-   </class>
+   <class name="EcalDigiHostCollection" rntupleStreamerMode="true"/>
    <class name="edm::Wrapper<EcalDigiHostCollection>" splitLevel="0"/>
 
    <class name="EcalDataArrayPhase2"/>
@@ -162,8 +160,6 @@
    <class name="EcalDigiPhase2HostCollection::Layout"/>
    <class name="EcalDigiPhase2SoA"/>
    <class name="EcalDigiPhase2SoA::View"/>
-   <class name="EcalDigiPhase2HostCollection" ClassVersion="3">
-     <version ClassVersion="3" checksum="2567280384"/>
-   </class>
+   <class name="EcalDigiPhase2HostCollection" rntupleStreamerMode="true"/>
    <class name="edm::Wrapper<EcalDigiPhase2HostCollection>" splitLevel="0"/>
 </lcgdict>
diff --git a/DataFormats/EcalRecHit/src/classes_def.xml b/DataFormats/EcalRecHit/src/classes_def.xml
index c70bbd1d347ca..d7327bf1d9808 100644
--- a/DataFormats/EcalRecHit/src/classes_def.xml
+++ b/DataFormats/EcalRecHit/src/classes_def.xml
@@ -39,7 +39,7 @@
   <class name="edm::Wrapper<edm::DetSetVector<EcalRecHit> >"/>
   <class name="edm::Wrapper<std::vector<std::vector<edm::DetSet<EcalRecHit> > > >"/>
 
-  <class name="EcalUncalibratedRecHitHostCollection"/>
+  <class name="EcalUncalibratedRecHitHostCollection" rntupleStreamerMode="true"/>
   <!-- EcalUncalibratedRecHitHostCollection::Layout must be listed before the aliased-to type -->
   <class name="EcalUncalibratedRecHitHostCollection::Layout"/>
   <class name="EcalOotAmpArray"/>
@@ -47,7 +47,7 @@
   <class name="EcalUncalibratedRecHitSoA::View"/>
   <class name="edm::Wrapper<EcalUncalibratedRecHitHostCollection>" splitLevel="0"/>
 
-  <class name="EcalRecHitHostCollection"/>
+  <class name="EcalRecHitHostCollection" rntupleStreamerMode="true"/>
   <!-- EcalRecHitHostCollection::Layout must be listed before the aliased-to type -->
   <class name="EcalRecHitHostCollection::Layout"/>
   <class name="EcalRecHitSoA"/>
diff --git a/DataFormats/EgammaReco/interface/EgammaTrigger.h b/DataFormats/EgammaReco/interface/EgammaTrigger.h
index f0eb53f505d08..fba9144e6f717 100644
--- a/DataFormats/EgammaReco/interface/EgammaTrigger.h
+++ b/DataFormats/EgammaReco/interface/EgammaTrigger.h
@@ -9,11 +9,10 @@
  *
  */
 #include "DataFormats/EgammaReco/interface/EgammaTriggerFwd.h"
+#include "DataFormats/EgammaReco/interface/SuperClusterFwd.h"
 
 namespace reco {
 
-  class SuperCluster;
-
   namespace egamma {
     enum { L1Single = 0, L1Double, L1RelaxedDouble, IsolatedL1 };
     template <unsigned char L1>
diff --git a/DataFormats/HGCalReco/src/classes_def.xml b/DataFormats/HGCalReco/src/classes_def.xml
index 09e400dbe1810..92c3f0cd6a741 100644
--- a/DataFormats/HGCalReco/src/classes_def.xml
+++ b/DataFormats/HGCalReco/src/classes_def.xml
@@ -74,14 +74,14 @@
   <class name="edm::Wrapper<TICLCandidate>" />
   <class name="edm::Wrapper<std::vector<TICLCandidate> >" />
 
-  <class name="MtdHostCollection"/>
+  <class name="MtdHostCollection" rntupleStreamerMode="true"/>
   <!-- MtdHostCollection::Layout must be listed before the aliased-to type -->
   <class name="MtdHostCollection::Layout"/>
   <class name="MtdSoA"/>
   <class name="MtdSoA::View"/>
   <class name="edm::Wrapper<MtdHostCollection>" splitLevel="0"/>
 
-  <class name="HGCalSoARecHitsHostCollection"/>
+  <class name="HGCalSoARecHitsHostCollection" rntupleStreamerMode="true"/>
   <!-- HGCalSoARecHitsHostCollection::Layout must be listed before the aliased-to type -->
   <class name="HGCalSoARecHitsHostCollection::Layout"/>
   <class name="HGCalSoARecHits"/>
diff --git a/DataFormats/HLTReco/interface/EgammaObject.h b/DataFormats/HLTReco/interface/EgammaObject.h
index d3df908c7ab1f..4f8472dc50ad9 100644
--- a/DataFormats/HLTReco/interface/EgammaObject.h
+++ b/DataFormats/HLTReco/interface/EgammaObject.h
@@ -5,14 +5,11 @@
 #include "DataFormats/EgammaReco/interface/SuperClusterFwd.h"
 #include "DataFormats/EgammaReco/interface/ElectronSeedFwd.h"
 #include "DataFormats/GsfTrackReco/interface/GsfTrackFwd.h"
+#include "DataFormats/RecoCandidate/interface/RecoEcalCandidateFwd.h"
 
 #include <vector>
 #include <string>
 
-namespace reco {
-  class RecoEcalCandidate;
-}
-
 namespace trigger {
   class EgammaObject : public TriggerObject {
   public:
diff --git a/DataFormats/HcalDigi/src/classes_def.xml b/DataFormats/HcalDigi/src/classes_def.xml
index 4b5ce52dca15a..aa664b497c3ce 100644
--- a/DataFormats/HcalDigi/src/classes_def.xml
+++ b/DataFormats/HcalDigi/src/classes_def.xml
@@ -115,14 +115,14 @@
    <class name="edm::Wrapper<HcalUMNioDigi>" splitLevel="0"/>
 
 
-  <class name="hcal::Phase1DigiHostCollection"/>
+  <class name="hcal::Phase1DigiHostCollection" rntupleStreamerMode="true"/>
   <!-- hcal::Phase1DigiHostCollection::Layout must be listed before the aliased-to type -->
   <class name="hcal::Phase1DigiHostCollection::Layout"/>
   <class name="hcal::HcalPhase1DigiSoA"/>
   <class name="hcal::HcalPhase1DigiSoA::View"/>
   <class name="edm::Wrapper<hcal::Phase1DigiHostCollection>" splitLevel="0"/>
 
-  <class name="hcal::Phase0DigiHostCollection"/> 
+  <class name="hcal::Phase0DigiHostCollection" rntupleStreamerMode="true"/> 
   <!-- hcal::Phase0DigiHostCollection::Layout must be listed before the aliased-to type -->
   <class name="hcal::Phase0DigiHostCollection::Layout"/>
   <class name="hcal::HcalPhase0DigiSoA"/>
diff --git a/DataFormats/HcalRecHit/src/classes_def.xml b/DataFormats/HcalRecHit/src/classes_def.xml
index 38a58e28f47d1..88e0e8d648453 100644
--- a/DataFormats/HcalRecHit/src/classes_def.xml
+++ b/DataFormats/HcalRecHit/src/classes_def.xml
@@ -120,7 +120,7 @@
   <class name="edm::reftobase::Holder<CaloRecHit,edm::Ref<edm::SortedCollection<HORecHit,edm::StrictWeakOrdering<HORecHit> >,HORecHit,edm::refhelper::FindUsingAdvance<edm::SortedCollection<HORecHit,edm::StrictWeakOrdering<HORecHit> >,HORecHit> > >" />
   <class name="edm::reftobase::Holder<CaloRecHit,edm::Ref<edm::SortedCollection<HBHERecHit,edm::StrictWeakOrdering<HBHERecHit> >,HBHERecHit,edm::refhelper::FindUsingAdvance<edm::SortedCollection<HBHERecHit,edm::StrictWeakOrdering<HBHERecHit> >,HBHERecHit> > >" />
 
-  <class name="hcal::RecHitHostCollection" />
+  <class name="hcal::RecHitHostCollection" rntupleStreamerMode="true"/>
   <!-- hcal::RecHitHostCollection::Layout must be listed before the aliased-to type -->
   <class name="hcal::RecHitHostCollection::Layout" />
   <class name="hcal::HcalRecHitSoA"/>
diff --git a/DataFormats/JetReco/interface/CaloJetFwd.h b/DataFormats/JetReco/interface/CaloJetFwd.h
new file mode 100644
index 0000000000000..e242d3de59a04
--- /dev/null
+++ b/DataFormats/JetReco/interface/CaloJetFwd.h
@@ -0,0 +1,7 @@
+#ifndef DataFormats_JetReco_CaloJetFwd_h
+#define DataFormats_JetReco_CaloJetFwd_h
+namespace reco {
+  class CaloJet;
+}
+
+#endif
diff --git a/DataFormats/JetReco/interface/GenJetCollection.h b/DataFormats/JetReco/interface/GenJetCollection.h
index a382d7a9a9599..6c027d7fa4a5d 100644
--- a/DataFormats/JetReco/interface/GenJetCollection.h
+++ b/DataFormats/JetReco/interface/GenJetCollection.h
@@ -11,7 +11,6 @@
 #include "DataFormats/JetReco/interface/GenJet.h"  //INCLUDECHECKER:SKIP
 
 namespace reco {
-  class GenJet;
   /// collection of GenJet objects
   typedef std::vector<GenJet> GenJetCollection;
   /// edm references
diff --git a/DataFormats/JetReco/interface/GenJetFwd.h b/DataFormats/JetReco/interface/GenJetFwd.h
new file mode 100644
index 0000000000000..b7c18220156bc
--- /dev/null
+++ b/DataFormats/JetReco/interface/GenJetFwd.h
@@ -0,0 +1,6 @@
+#ifndef DataFormats_JetReco_GenJetFwd_h
+#define DataFormats_JetReco_GenJetFwd_h
+namespace reco {
+  class GenJet;
+}
+#endif
diff --git a/DataFormats/JetReco/interface/JetFwd.h b/DataFormats/JetReco/interface/JetFwd.h
new file mode 100644
index 0000000000000..f815e76e5f481
--- /dev/null
+++ b/DataFormats/JetReco/interface/JetFwd.h
@@ -0,0 +1,6 @@
+#ifndef DataFormats_JetReco_JetFwd_h
+#define DataFormats_JetReco_JetFwd_h
+namespace reco {
+  class Jet;
+}  // namespace reco
+#endif
diff --git a/DataFormats/MuonReco/interface/MuonSelectors.h b/DataFormats/MuonReco/interface/MuonSelectors.h
index efe6481f0582c..8d6db20b52c94 100644
--- a/DataFormats/MuonReco/interface/MuonSelectors.h
+++ b/DataFormats/MuonReco/interface/MuonSelectors.h
@@ -7,12 +7,9 @@
 // Original Author:  Jake Ribnik, Dmytro Kovalskyi
 
 #include "DataFormats/MuonReco/interface/Muon.h"
+#include "DataFormats/VertexReco/interface/VertexFwd.h"
 #include <string>
 
-namespace reco {
-  class Vertex;
-}
-
 namespace muon {
   /// Selector type
   enum SelectionType {
diff --git a/DataFormats/ParticleFlowReco/interface/PFV0.h b/DataFormats/ParticleFlowReco/interface/PFV0.h
index 9253feb8bb67e..15cce1bcbf3eb 100644
--- a/DataFormats/ParticleFlowReco/interface/PFV0.h
+++ b/DataFormats/ParticleFlowReco/interface/PFV0.h
@@ -7,11 +7,10 @@
 #include "DataFormats/ParticleFlowReco/interface/PFV0Fwd.h"
 #include "DataFormats/Candidate/interface/VertexCompositeCandidate.h"
 #include "DataFormats/Candidate/interface/VertexCompositeCandidateFwd.h"
+#include "DataFormats/EgammaCandidates/interface/ConversionFwd.h"
 #include <iostream>
 #include <vector>
 
-class Conversion;
-
 namespace reco {
 
   class PFV0 {
diff --git a/DataFormats/ParticleFlowReco/src/classes_serial_def.xml b/DataFormats/ParticleFlowReco/src/classes_serial_def.xml
index 8494ea92aff6c..593b26dcac087 100644
--- a/DataFormats/ParticleFlowReco/src/classes_serial_def.xml
+++ b/DataFormats/ParticleFlowReco/src/classes_serial_def.xml
@@ -1,26 +1,26 @@
 <lcgdict>
-  <class name="reco::CaloRecHitHostCollection"/>
+  <class name="reco::CaloRecHitHostCollection" rntupleStreamerMode="true"/>
   <!-- reco::CaloRecHitHostCollection::Layout must be listed before the aliased-to type -->
   <class name="reco::CaloRecHitHostCollection::Layout"/>
   <class name="reco::CaloRecHitSoA"/>
   <class name="reco::CaloRecHitSoA::View"/>
   <class name="edm::Wrapper<reco::CaloRecHitHostCollection>" splitLevel="0"/>
 
-  <class name="reco::PFRecHitHostCollection"/>
+  <class name="reco::PFRecHitHostCollection" rntupleStreamerMode="true"/>
   <!-- reco::PFRecHitHostCollection::Layout must be listed before the aliased-to type -->
   <class name="reco::PFRecHitHostCollection::Layout"/>
   <class name="reco::PFRecHitSoA"/>
   <class name="reco::PFRecHitSoA::View"/>
   <class name="edm::Wrapper<reco::PFRecHitHostCollection>" splitLevel="0"/>
 
-  <class name="reco::PFClusterHostCollection"/>
+  <class name="reco::PFClusterHostCollection" rntupleStreamerMode="true"/>
   <!-- reco::PFClusterHostCollection::Layout must be listed before the aliased-to type -->
   <class name="reco::PFClusterHostCollection::Layout"/>
   <class name="reco::PFClusterSoA"/>
   <class name="reco::PFClusterSoA::View"/>
   <class name="edm::Wrapper<reco::PFClusterHostCollection>" splitLevel="0"/>
 
-  <class name="reco::PFRecHitFractionHostCollection"/>
+  <class name="reco::PFRecHitFractionHostCollection" rntupleStreamerMode="true"/>
   <!-- reco::PFRecHitFractionHostCollection::Layout must be listed before the aliased-to type -->
   <class name="reco::PFRecHitFractionHostCollection::Layout"/>
   <class name="reco::PFRecHitFractionSoA"/>
diff --git a/DataFormats/Portable/README.md b/DataFormats/Portable/README.md
index dda335e6fb068..b59973e46c92b 100644
--- a/DataFormats/Portable/README.md
+++ b/DataFormats/Portable/README.md
@@ -36,6 +36,8 @@ SET_PORTABLEHOSTOBJECT_READ_RULES(portabletest::TestHostObject);
 ```
 **Note:** The dictionary for `portabletest::TestHostObject::Product` (using the same type alias as in the registration macro above) must be placed in the `classes_def.xml` file before the type that `Product` aliases.
 
+**Note:** The dictionary for `portabletest::TestHostObject` in `classes_def.xml` needs `rntupleStreamerMode="true"` attribute in order to be storable with RNTuple.
+
 
 `PortableHostObject<T>` objects can also be read back in "bare ROOT" mode, without any dictionaries.
 They have no implicit or explicit references to alpaka (neither as part of the class signature nor as part of its name).
@@ -97,6 +99,8 @@ SET_PORTABLEHOSTCOLLECTION_READ_RULES(portabletest::TestHostCollection);
 ```
 **Note:** The dictionary for `portabletest::TestHostCollection::Layout` (using the same type alias as in the registration macro above) must be placed in the `classes_def.xml` file before the type that `Layout` aliases.
 
+**Note:** The dictionary for `portabletest::TestHostCollection` in `classes_def.xml` needs `rntupleStreamerMode="true"` attribute in order to be storable with RNTuple.
+
 
 `PortableHostCollection<T>` collections can also be read back in "bare ROOT" mode, without any dictionaries.
 They have no implicit or explicit references to alpaka (neither as part of the class signature nor as part of its name).
diff --git a/DataFormats/Portable/scripts/portableHostCollectionHints b/DataFormats/Portable/scripts/portableHostCollectionHints
index 895831d08e20d..902ae20354ce1 100755
--- a/DataFormats/Portable/scripts/portableHostCollectionHints
+++ b/DataFormats/Portable/scripts/portableHostCollectionHints
@@ -13,7 +13,7 @@ for i in range(len(layouts)):
 print("In <module>/src/classes_def.xml (with necessary includes in <module>/src/classes.h):\n")
 print("<lcgdict>")
 print("  <!-- Collection declaration for dictionary -->")
-print("  <class name=\"%s\"/>"% collectionName)
+print("  <class name=\"%s\" rntupleStreamerMode=\"true\"/>"% collectionName)
 print("  <!-- %s::Layout must be listed before the aliased-to type -->"% collectionName)
 print("  <class name=\"%s::Layout\"/>"% collectionName)
 print()
diff --git a/DataFormats/PortableTestObjects/src/classes_def.xml b/DataFormats/PortableTestObjects/src/classes_def.xml
index 8d6168cc12600..50473ee0905b0 100644
--- a/DataFormats/PortableTestObjects/src/classes_def.xml
+++ b/DataFormats/PortableTestObjects/src/classes_def.xml
@@ -1,20 +1,20 @@
 <lcgdict>
-  <class name="portabletest::TestHostCollection"/>
+  <class name="portabletest::TestHostCollection" rntupleStreamerMode="true"/>
   <!-- portabletest::TestHostCollection::Layout alias must be listed before the aliased-to type -->
   <class name="portabletest::TestHostCollection::Layout"/>
   <class name="edm::Wrapper<portabletest::TestHostCollection>" splitLevel="0"/>
 
-  <class name="portabletest::TestHostCollection2"/>
+  <class name="portabletest::TestHostCollection2" rntupleStreamerMode="true"/>
   <!-- portabletest::TestHostCollection2::Layout alias must be listed before the aliased-to type -->
   <class name="portabletest::TestHostCollection2::Layout"/>
   <class name="edm::Wrapper<portabletest::TestHostCollection2>" splitLevel="0"/>
 
-  <class name="portabletest::TestHostCollection3"/>
+  <class name="portabletest::TestHostCollection3" rntupleStreamerMode="true"/>
   <!-- portabletest::TestHostCollection3::Layout alias must be listed before the aliased-to type -->
   <class name="portabletest::TestHostCollection3::Layout"/>
   <class name="edm::Wrapper<portabletest::TestHostCollection3>" splitLevel="0"/>
 
-  <class name="portabletest::TestHostObject"/>
+  <class name="portabletest::TestHostObject" rntupleStreamerMode="true"/>
   <!-- portabletest::TestHostObject::Product alias must be listed before the aliased-to type -->
   <!-- TODO: we should find a better way than replicating the class versions and checksums -->
   <class name="portabletest::TestHostObject::Product" ClassVersion="3">
@@ -35,7 +35,7 @@
   <class name="edm::Wrapper<portabletest::TestProductWithPtr<alpaka_common::DevHost>>" persistent="false"/>
 
   <!-- Torch SoAs and Collections -->
-  <class name="portabletest::ParticleHostCollection"/>
+  <class name="portabletest::ParticleHostCollection" rntupleStreamerMode="true"/>
   <!-- portabletest::ParticleHostCollection::Layout must be listed before the aliased-to type -->
   <class name="portabletest::ParticleHostCollection::Layout"/>
   <class name="portabletest::ParticleSoA"/>
@@ -43,7 +43,7 @@
   <class name="portabletest::ParticleSoA::ConstView"/>
   <class name="edm::Wrapper<portabletest::ParticleHostCollection>" splitLevel="0"/>
 
-  <class name="portabletest::SimpleNetHostCollection"/>
+  <class name="portabletest::SimpleNetHostCollection" rntupleStreamerMode="true"/>
   <!-- portabletest::SimpleNetHostCollection::Layout must be listed before the aliased-to type -->
   <class name="portabletest::SimpleNetHostCollection::Layout"/>
   <class name="portabletest::SimpleNetSoA"/>
@@ -51,7 +51,7 @@
   <class name="portabletest::SimpleNetSoA::ConstView"/>
   <class name="edm::Wrapper<portabletest::SimpleNetHostCollection>" splitLevel="0"/>
 
-  <class name="portabletest::MultiHeadNetHostCollection"/>
+  <class name="portabletest::MultiHeadNetHostCollection" rntupleStreamerMode="true"/>
   <!-- portabletest::MultiHeadNetHostCollection::Layout must be listed before the aliased-to type -->
   <class name="portabletest::MultiHeadNetHostCollection::Layout"/>
   <class name="portabletest::MultiHeadNetSoA"/>
@@ -59,7 +59,7 @@
   <class name="portabletest::MultiHeadNetSoA::ConstView"/>
   <class name="edm::Wrapper<portabletest::MultiHeadNetHostCollection>" splitLevel="0"/>
 
-  <class name="portabletest::ImageHostCollection"/>
+  <class name="portabletest::ImageHostCollection" rntupleStreamerMode="true"/>
   <!-- portabletest::ImageHostCollection::Layout must be listed before the aliased-to type -->
   <class name="portabletest::ImageHostCollection::Layout"/>
   <class name="portabletest::ImageSoA"/>
@@ -67,7 +67,7 @@
   <class name="portabletest::ImageSoA::ConstView"/>
   <class name="edm::Wrapper<portabletest::ImageHostCollection>" splitLevel="0"/>
 
-  <class name="portabletest::LogitsHostCollection"/>
+  <class name="portabletest::LogitsHostCollection" rntupleStreamerMode="true"/>
   <!-- portabletest::LogitsHostCollection::Layout must be listed before the aliased-to type -->
   <class name="portabletest::LogitsHostCollection::Layout"/>
   <class name="portabletest::LogitsSoA"/>
@@ -75,7 +75,7 @@
   <class name="portabletest::LogitsSoA::ConstView"/>
   <class name="edm::Wrapper<portabletest::LogitsHostCollection>" splitLevel="0"/>
 
-  <class name="portabletest::MaskHostCollection"/>
+  <class name="portabletest::MaskHostCollection" rntupleStreamerMode="true"/>
   <!-- portabletest::MaskHostCollection::Layout must be listed before the aliased-to type -->
   <class name="portabletest::MaskHostCollection::Layout"/>
   <class name="portabletest::MaskSoA"/>
diff --git a/DataFormats/SiPixelClusterSoA/src/classes_def.xml b/DataFormats/SiPixelClusterSoA/src/classes_def.xml
index 587e9c7fd05a0..2b5553610d0ab 100644
--- a/DataFormats/SiPixelClusterSoA/src/classes_def.xml
+++ b/DataFormats/SiPixelClusterSoA/src/classes_def.xml
@@ -1,5 +1,5 @@
 <lcgdict>
-  <class name="PortableHostCollection<SiPixelClustersSoA>"/>
+  <class name="PortableHostCollection<SiPixelClustersSoA>" rntupleStreamerMode="true"/>
   <!-- PortableHostCollection<SiPixelClustersSoA>::Layout must be listed before the aliased-to type -->
   <class name="PortableHostCollection<SiPixelClustersSoA>::Layout"/>
   <class name="SiPixelClustersSoA"/>
diff --git a/DataFormats/SiPixelDigiSoA/src/classes_def.xml b/DataFormats/SiPixelDigiSoA/src/classes_def.xml
index bfd5ec3f60375..f4d0fd97450c5 100644
--- a/DataFormats/SiPixelDigiSoA/src/classes_def.xml
+++ b/DataFormats/SiPixelDigiSoA/src/classes_def.xml
@@ -1,5 +1,5 @@
 <lcgdict>
-  <class name="PortableHostCollection<SiPixelDigisSoA>"/>
+  <class name="PortableHostCollection<SiPixelDigisSoA>" rntupleStreamerMode="true"/>
   <!-- PortableHostCollection<SiPixelDigisSoA>::Layout must be listed before the aliased-to type -->
   <class name="PortableHostCollection<SiPixelDigisSoA>::Layout"/>
   <class name="SiPixelDigisSoA"/>
@@ -7,7 +7,7 @@
   <class name="SiPixelDigisHost"/>
   <class name="edm::Wrapper<SiPixelDigisHost>" splitLevel="0"/>
 
-  <class name="PortableHostCollection<SiPixelDigiErrorsSoA>"/>
+  <class name="PortableHostCollection<SiPixelDigiErrorsSoA>" rntupleStreamerMode="true"/>
   <!-- PortableHostCollection<SiPixelDigiErrorsSoA>::Layout must be listed before the aliased-to type -->
   <class name="PortableHostCollection<SiPixelDigiErrorsSoA>::Layout"/>
   <class name="SiPixelDigiErrorsSoA"/>
diff --git a/DataFormats/SiStripClusterSoA/src/classes_def.xml b/DataFormats/SiStripClusterSoA/src/classes_def.xml
index a5fee8d19ae11..06ed1a5a7cfbf 100644
--- a/DataFormats/SiStripClusterSoA/src/classes_def.xml
+++ b/DataFormats/SiStripClusterSoA/src/classes_def.xml
@@ -2,6 +2,6 @@
   <!-- ::Layout alias must be listed before the aliased-to type -->
   <class name="sistrip::SiStripClusterHost::Layout"/>
   <class name="sistrip::SiStripClusterSoALayout<128,false>"/>
-  <class name="sistrip::SiStripClusterHost"/>
+  <class name="sistrip::SiStripClusterHost" rntupleStreamerMode="true"/>
   <class name="edm::Wrapper<sistrip::SiStripClusterHost>" splitLevel="0"/>
 </lcgdict>
diff --git a/DataFormats/SiStripDigiSoA/src/classes_def.xml b/DataFormats/SiStripDigiSoA/src/classes_def.xml
index e8534e51ee9c7..97bfb016210b4 100644
--- a/DataFormats/SiStripDigiSoA/src/classes_def.xml
+++ b/DataFormats/SiStripDigiSoA/src/classes_def.xml
@@ -2,6 +2,6 @@
   <!-- ::Layout alias must be listed before the aliased-to type -->
   <class name="sistrip::SiStripDigiHost::Layout"/>
   <class name="sistrip::SiStripDigiSoALayout<128,false>"/>
-  <class name="sistrip::SiStripDigiHost"/>
+  <class name="sistrip::SiStripDigiHost" rntupleStreamerMode="true"/>
   <class name="edm::Wrapper<sistrip::SiStripDigiHost>" splitLevel="0"/>
 </lcgdict>
diff --git a/FWIO/RNTupleTempInput/src/RootFile.cc b/FWIO/RNTupleTempInput/src/RootFile.cc
index 9899ddcc75203..443e3d2e4d97a 100644
--- a/FWIO/RNTupleTempInput/src/RootFile.cc
+++ b/FWIO/RNTupleTempInput/src/RootFile.cc
@@ -57,9 +57,6 @@
 #include "FWCore/ServiceRegistry/interface/ModuleCallingContext.h"
 
 //used for backward compatibility
-#include "DataFormats/Provenance/interface/EventAux.h"
-#include "DataFormats/Provenance/interface/LuminosityBlockAux.h"
-#include "DataFormats/Provenance/interface/RunAux.h"
 #include "FWCore/ParameterSet/interface/ParameterSetConverter.h"
 
 #include "Rtypes.h"
@@ -1064,16 +1061,8 @@ namespace edm::rntuple_temp {
       // Already read.
       return eventAuxCache_;
     }
-    if (fileFormatVersion().newAuxiliary()) {
-      EventAuxiliary* pEvAux = &eventAuxCache_;
-      eventTree_.fillAux<EventAuxiliary>(pEvAux);
-    } else {
-      // for backward compatibility.
-      EventAux eventAux;
-      EventAux* pEvAux = &eventAux;
-      eventTree_.fillAux<EventAux>(pEvAux);
-      conversion(eventAux, eventAuxCache_);
-    }
+    EventAuxiliary* pEvAux = &eventAuxCache_;
+    eventTree_.fillAux<EventAuxiliary>(pEvAux);
     lastEventEntryNumberRead_ = eventTree_.entryNumber();
     return eventAuxCache_;
   }
@@ -1139,15 +1128,8 @@ namespace edm::rntuple_temp {
 
   std::shared_ptr<LuminosityBlockAuxiliary> RootFile::fillLumiAuxiliary() {
     auto lumiAuxiliary = std::make_shared<LuminosityBlockAuxiliary>();
-    if (fileFormatVersion().newAuxiliary()) {
-      LuminosityBlockAuxiliary* pLumiAux = lumiAuxiliary.get();
-      lumiTree_.fillAux<LuminosityBlockAuxiliary>(pLumiAux);
-    } else {
-      LuminosityBlockAux lumiAux;
-      LuminosityBlockAux* pLumiAux = &lumiAux;
-      lumiTree_.fillAux<LuminosityBlockAux>(pLumiAux);
-      conversion(lumiAux, *lumiAuxiliary);
-    }
+    LuminosityBlockAuxiliary* pLumiAux = lumiAuxiliary.get();
+    lumiTree_.fillAux<LuminosityBlockAuxiliary>(pLumiAux);
     if (daqProvenanceHelper_) {
       lumiAuxiliary->setProcessHistoryID(daqProvenanceHelper_->mapProcessHistoryID(lumiAuxiliary->processHistoryID()));
     }
@@ -1159,15 +1141,8 @@ namespace edm::rntuple_temp {
 
   std::shared_ptr<RunAuxiliary> RootFile::fillRunAuxiliary() {
     auto runAuxiliary = std::make_shared<RunAuxiliary>();
-    if (fileFormatVersion().newAuxiliary()) {
-      RunAuxiliary* pRunAux = runAuxiliary.get();
-      runTree_.fillAux<RunAuxiliary>(pRunAux);
-    } else {
-      RunAux runAux;
-      RunAux* pRunAux = &runAux;
-      runTree_.fillAux<RunAux>(pRunAux);
-      conversion(runAux, *runAuxiliary);
-    }
+    RunAuxiliary* pRunAux = runAuxiliary.get();
+    runTree_.fillAux<RunAuxiliary>(pRunAux);
     if (daqProvenanceHelper_) {
       runAuxiliary->setProcessHistoryID(daqProvenanceHelper_->mapProcessHistoryID(runAuxiliary->processHistoryID()));
     }
diff --git a/FWIO/RNTupleTempInput/src/RootRNTuple.h b/FWIO/RNTupleTempInput/src/RootRNTuple.h
index 0ae3f07d8d255..f5717378d93d4 100644
--- a/FWIO/RNTupleTempInput/src/RootRNTuple.h
+++ b/FWIO/RNTupleTempInput/src/RootRNTuple.h
@@ -10,6 +10,9 @@ RootRNTuple.h // used by ROOT input sources
 #include "DataFormats/Provenance/interface/ProductDescription.h"
 #include "DataFormats/Provenance/interface/BranchID.h"
 #include "DataFormats/Provenance/interface/IndexIntoFile.h"
+#include "DataFormats/Provenance/interface/EventAuxiliary.h"
+#include "DataFormats/Provenance/interface/LuminosityBlockAuxiliary.h"
+#include "DataFormats/Provenance/interface/RunAuxiliary.h"
 #include "FWCore/Framework/interface/Frameworkfwd.h"
 #include "FWCore/ServiceRegistry/interface/ServiceRegistryfwd.h"
 #include "FWCore/Utilities/interface/BranchType.h"
@@ -25,6 +28,7 @@ RootRNTuple.h // used by ROOT input sources
 #include <vector>
 #include <unordered_set>
 #include <unordered_map>
+#include <variant>
 
 #include "ROOT/RNTuple.hxx"
 #include "ROOT/RNTupleReader.hxx"
@@ -141,7 +145,11 @@ namespace edm::rntuple_temp {
     template <typename T>
     void fillAux(T*& pAux) {
       try {
-        auto view = reader_->GetView(auxDesc_, pAux);
+        if (std::holds_alternative<std::monostate>(auxView_)) {
+          auxView_ = reader_->GetView(auxDesc_, pAux);
+        }
+        auto& view = std::get<ROOT::RNTupleView<T>>(auxView_);
+        view.BindRawPtr(pAux);
         view(entryNumber_);
       } catch (cms::Exception const& e) {
         throw Exception(errors::FileReadError, "", e);
@@ -201,6 +209,11 @@ namespace edm::rntuple_temp {
     unsigned long treeAutoFlush_ = 0;
     bool promptRead_;
     std::unique_ptr<RootDelayedReaderBase> rootDelayedReader_;
+    std::variant<std::monostate,
+                 ROOT::RNTupleView<edm::EventAuxiliary>,
+                 ROOT::RNTupleView<edm::LuminosityBlockAuxiliary>,
+                 ROOT::RNTupleView<edm::RunAuxiliary>>
+        auxView_;
   };
 }  // namespace edm::rntuple_temp
 #endif
diff --git a/Fireworks/Calo/interface/FWTauProxyBuilderBase.h b/Fireworks/Calo/interface/FWTauProxyBuilderBase.h
index 8952abe8cad41..7a8c51dca743c 100644
--- a/Fireworks/Calo/interface/FWTauProxyBuilderBase.h
+++ b/Fireworks/Calo/interface/FWTauProxyBuilderBase.h
@@ -22,13 +22,13 @@
 #include "Fireworks/Core/interface/FWProxyBuilderBase.h"
 #include "Fireworks/Core/interface/FWViewType.h"
 #include "Fireworks/Calo/interface/scaleMarker.h"
+#include "DataFormats/JetReco/interface/JetFwd.h"
 #include <vector>
 
 class TEveScalableStraightLineSet;
 class FWViewContext;
 
 namespace reco {
-  class Jet;
   class BaseTau;
 }  // namespace reco
 
diff --git a/Fireworks/Calo/interface/makeEveJetCone.h b/Fireworks/Calo/interface/makeEveJetCone.h
index f89cdd6455cc2..9486001c6e158 100644
--- a/Fireworks/Calo/interface/makeEveJetCone.h
+++ b/Fireworks/Calo/interface/makeEveJetCone.h
@@ -21,14 +21,11 @@
 // system include files
 
 // user include files
+#include "DataFormats/JetReco/interface/JetFwd.h"
 
 // forward declarations
 class TEveJetCone;
 
-namespace reco {
-  class Jet;
-}
-
 namespace fireworks {
   class Context;
   TEveJetCone* makeEveJetCone(const reco::Jet& iData, const fireworks::Context& context);
diff --git a/Fireworks/Core/interface/FWBeamSpot.h b/Fireworks/Core/interface/FWBeamSpot.h
index 1dfce0e3b1ef8..52cea23e83a8a 100644
--- a/Fireworks/Core/interface/FWBeamSpot.h
+++ b/Fireworks/Core/interface/FWBeamSpot.h
@@ -1,12 +1,11 @@
 #ifndef Fireworks_Tracks_FWBeamSpot_h
 #define Fireworks_Tracks_FWBeamSpot_h
 
+#include "DataFormats/BeamSpot/interface/BeamSpotFwd.h"
+
 namespace edm {
   class EventBase;
 }
-namespace reco {
-  class BeamSpot;
-}
 
 class FWBeamSpot {
 public:
diff --git a/Fireworks/Electrons/plugins/FWConvTrackHitsDetailView.h b/Fireworks/Electrons/plugins/FWConvTrackHitsDetailView.h
index 4646d9ac139ae..fc2f1c3f2f41a 100644
--- a/Fireworks/Electrons/plugins/FWConvTrackHitsDetailView.h
+++ b/Fireworks/Electrons/plugins/FWConvTrackHitsDetailView.h
@@ -11,15 +11,12 @@
 #include "Fireworks/Core/interface/FWDetailViewGL.h"
 #include "Fireworks/Core/interface/CSGActionSupervisor.h"
 #include "DataFormats/TrackReco/interface/TrackFwd.h"
+#include "DataFormats/EgammaCandidates/interface/ConversionFwd.h"
 #include "TVector3.h"
 
 class TGLEmbeddedViewer;
 class TGTextButton;
 
-namespace reco {
-  class Conversion;
-}
-
 class FWConvTrackHitsDetailView : public FWDetailViewGL<reco::Conversion>, public CSGActionSupervisor {
 public:
   FWConvTrackHitsDetailView();
diff --git a/Fireworks/Electrons/plugins/FWElectronDetailView.h b/Fireworks/Electrons/plugins/FWElectronDetailView.h
index eb4462b940fb4..7bf3dd675f95d 100644
--- a/Fireworks/Electrons/plugins/FWElectronDetailView.h
+++ b/Fireworks/Electrons/plugins/FWElectronDetailView.h
@@ -16,6 +16,7 @@
 // user include files
 #include "Fireworks/Core/interface/FWDetailViewGL.h"
 #include "DataFormats/EgammaReco/interface/BasicCluster.h"
+#include "DataFormats/EgammaCandidates/interface/GsfElectronFwd.h"
 
 class TEveCaloDataVec;
 class TEveCaloLego;
@@ -24,10 +25,6 @@ class FWECALDetailViewBuilder;
 class TEveCaloData;
 class TGSlider;
 
-namespace reco {
-  class GsfElectron;
-}
-
 class FWElectronDetailView : public FWDetailViewGL<reco::GsfElectron> {
 public:
   FWElectronDetailView();
diff --git a/Fireworks/Electrons/plugins/FWPhotonDetailView.h b/Fireworks/Electrons/plugins/FWPhotonDetailView.h
index 76e09991b0479..9ae35460b7441 100644
--- a/Fireworks/Electrons/plugins/FWPhotonDetailView.h
+++ b/Fireworks/Electrons/plugins/FWPhotonDetailView.h
@@ -14,12 +14,10 @@
 
 // user include files
 #include "Fireworks/Core/interface/FWDetailViewGL.h"
+#include "DataFormats/EgammaCandidates/interface/PhotonFwd.h"
 
 class FWECALDetailViewBuilder;
 class TEveCaloData;
-namespace reco {
-  class Photon;
-}
 
 class FWPhotonDetailView : public FWDetailViewGL<reco::Photon> {
 public:
diff --git a/Fireworks/Muons/interface/FWMuonBuilder.h b/Fireworks/Muons/interface/FWMuonBuilder.h
index edea62c6ab0b1..2ccc2b898a955 100644
--- a/Fireworks/Muons/interface/FWMuonBuilder.h
+++ b/Fireworks/Muons/interface/FWMuonBuilder.h
@@ -7,11 +7,9 @@
 //
 //
 #include "Fireworks/Core/interface/FWEvePtr.h"
+#include "DataFormats/MuonReco/interface/MuonFwd.h"
 
 // forward declarations
-namespace reco {
-  class Muon;
-}
 
 class FWEventItem;
 class TEveElementList;
diff --git a/Fireworks/Muons/plugins/FWMuonDetailView.h b/Fireworks/Muons/plugins/FWMuonDetailView.h
index afd955c305dcb..c0c0ff8ff3357 100644
--- a/Fireworks/Muons/plugins/FWMuonDetailView.h
+++ b/Fireworks/Muons/plugins/FWMuonDetailView.h
@@ -9,12 +9,10 @@
 
 // user include files
 #include "Fireworks/Core/interface/FWDetailViewGL.h"
+#include "DataFormats/MuonReco/interface/MuonFwd.h"
 
 class FWECALDetailViewBuilder;
 class TEveCaloData;
-namespace reco {
-  class Muon;
-}
 
 class FWMuonDetailView : public FWDetailViewGL<reco::Muon> {
 public:
diff --git a/Fireworks/ParticleFlow/interface/FWLegoEvePFCandidate.h b/Fireworks/ParticleFlow/interface/FWLegoEvePFCandidate.h
index f28cbc62d0485..7c84c8d537cb6 100644
--- a/Fireworks/ParticleFlow/interface/FWLegoEvePFCandidate.h
+++ b/Fireworks/ParticleFlow/interface/FWLegoEvePFCandidate.h
@@ -4,14 +4,11 @@
 #include "TEveLine.h"
 #include "TEveStraightLineSet.h"
 #include "Rtypes.h"
+#include "DataFormats/ParticleFlowCandidate/interface/PFCandidateFwd.h"
 
 class TEveTrack;
 class FWViewContext;
 
-namespace reco {
-  class PFCandidate;
-}
-
 namespace fireworks {
   class Context;
 }
diff --git a/Fireworks/ParticleFlow/interface/setTrackTypePF.h b/Fireworks/ParticleFlow/interface/setTrackTypePF.h
index fff79339fe726..0a623b698e5aa 100644
--- a/Fireworks/ParticleFlow/interface/setTrackTypePF.h
+++ b/Fireworks/ParticleFlow/interface/setTrackTypePF.h
@@ -11,9 +11,6 @@
 // user include files
 
 // forward declarations
-namespace reco {
-  class PFCandidate;
-}
 class TEveTrack;
 
 namespace fireworks {
diff --git a/Fireworks/ParticleFlow/plugins/FWPFCandidateDetailView.h b/Fireworks/ParticleFlow/plugins/FWPFCandidateDetailView.h
index 4bbfbb993f518..b36feabcaf33e 100644
--- a/Fireworks/ParticleFlow/plugins/FWPFCandidateDetailView.h
+++ b/Fireworks/ParticleFlow/plugins/FWPFCandidateDetailView.h
@@ -9,15 +9,14 @@
 #include "Fireworks/Core/interface/CSGActionSupervisor.h"
 
 #include "DataFormats/ParticleFlowCandidate/interface/PFCandidate.h"
+#include "DataFormats/ParticleFlowReco/interface/PFRecHitFwd.h"
+#include "DataFormats/ParticleFlowReco/interface/PFClusterFwd.h"
 class TGLEmbeddedViewer;
 class FWIntValueListener;
 class TEveCaloLego;
 class TGSlider;
 
 namespace reco {
-  //   class PFCandidate;
-  class PFRecHit;
-  class PFCluster;
   class PFRecTrack;
 }  // namespace reco
 
diff --git a/Fireworks/ParticleFlow/plugins/FWPFCandidateWithHitsProxyBuilder.h b/Fireworks/ParticleFlow/plugins/FWPFCandidateWithHitsProxyBuilder.h
index 8093fc55e1c62..2d132cf92d2e2 100644
--- a/Fireworks/ParticleFlow/plugins/FWPFCandidateWithHitsProxyBuilder.h
+++ b/Fireworks/ParticleFlow/plugins/FWPFCandidateWithHitsProxyBuilder.h
@@ -2,10 +2,7 @@
 //#include "DataFormats/HcalRecHit/interface/HcalRecHitCollections.h"
 #include "DataFormats/ParticleFlowReco/interface/PFRecHit.h"
 #include "DataFormats/ParticleFlowReco/interface/PFRecHitFwd.h"
-namespace reco {
-  class PFCandidate;
-  class PFRecHit;
-}  // namespace reco
+#include "DataFormats/ParticleFlowCandidate/interface/PFCandidateFwd.h"
 class CaloRecHit;
 
 class FWPFCandidateWithHitsProxyBuilder : public FWProxyBuilderBase {
diff --git a/HLTrigger/btau/plugins/HLTmmkFilter.h b/HLTrigger/btau/plugins/HLTmmkFilter.h
index e6aa8d0330713..23f0427dc94fa 100644
--- a/HLTrigger/btau/plugins/HLTmmkFilter.h
+++ b/HLTrigger/btau/plugins/HLTmmkFilter.h
@@ -22,6 +22,7 @@
 
 #include "HLTrigger/HLTcore/interface/HLTFilter.h"
 #include "DataFormats/RecoCandidate/interface/RecoChargedCandidateFwd.h"
+#include "DataFormats/Candidate/interface/CandidateOnlyFwd.h"
 #include "DataFormats/BeamSpot/interface/BeamSpot.h"
 #include "DataFormats/TrackReco/interface/TrackFwd.h"
 #include "TrackingTools/Records/interface/TransientTrackRecord.h"
@@ -33,10 +34,6 @@ namespace edm {
   class ConfigurationDescriptions;
 }
 
-namespace reco {
-  class Candidate;
-}  // namespace reco
-
 class FreeTrajectoryState;
 class MagneticField;
 
diff --git a/HLTrigger/btau/plugins/HLTmmkkFilter.h b/HLTrigger/btau/plugins/HLTmmkkFilter.h
index 08ad8775d5787..b975d2e11ac67 100644
--- a/HLTrigger/btau/plugins/HLTmmkkFilter.h
+++ b/HLTrigger/btau/plugins/HLTmmkkFilter.h
@@ -23,6 +23,7 @@
 #include "HLTrigger/HLTcore/interface/HLTFilter.h"
 #include "DataFormats/BeamSpot/interface/BeamSpot.h"
 #include "DataFormats/RecoCandidate/interface/RecoChargedCandidateFwd.h"
+#include "DataFormats/Candidate/interface/CandidateOnlyFwd.h"
 #include "DataFormats/TrackReco/interface/TrackFwd.h"
 #include "TrackingTools/Records/interface/TransientTrackRecord.h"
 #include "TrackingTools/TransientTrack/interface/TransientTrackBuilder.h"
@@ -33,10 +34,6 @@ namespace edm {
   class ConfigurationDescriptions;
 }
 
-namespace reco {
-  class Candidate;
-}  // namespace reco
-
 class FreeTrajectoryState;
 class MagneticField;
 
diff --git a/HLTrigger/btau/plugins/HLTmumutkVtxProducer.h b/HLTrigger/btau/plugins/HLTmumutkVtxProducer.h
index d15ce7b5ad0fb..15f27c7b50a72 100644
--- a/HLTrigger/btau/plugins/HLTmumutkVtxProducer.h
+++ b/HLTrigger/btau/plugins/HLTmumutkVtxProducer.h
@@ -20,6 +20,7 @@
 #include "FWCore/Framework/interface/Event.h"
 #include "FWCore/Framework/interface/EventSetup.h"
 #include "DataFormats/RecoCandidate/interface/RecoChargedCandidateFwd.h"
+#include "DataFormats/Candidate/interface/CandidateOnlyFwd.h"
 #include "DataFormats/TrackReco/interface/TrackFwd.h"
 #include "DataFormats/HLTReco/interface/TriggerFilterObjectWithRefs.h"
 #include "DataFormats/HLTReco/interface/TriggerRefsCollections.h"
@@ -35,10 +36,6 @@ namespace edm {
 
 // ----------------------------------------------------------------------
 
-namespace reco {
-  class Candidate;
-}  // namespace reco
-
 class FreeTrajectoryState;
 class MagneticField;
 
diff --git a/HLTrigger/btau/plugins/HLTmumutktkVtxProducer.h b/HLTrigger/btau/plugins/HLTmumutktkVtxProducer.h
index 286b1afd6667e..290478c30b7ca 100644
--- a/HLTrigger/btau/plugins/HLTmumutktkVtxProducer.h
+++ b/HLTrigger/btau/plugins/HLTmumutktkVtxProducer.h
@@ -15,6 +15,7 @@
 #include "FWCore/Framework/interface/Event.h"
 #include "FWCore/Framework/interface/EventSetup.h"
 #include "DataFormats/RecoCandidate/interface/RecoChargedCandidateFwd.h"
+#include "DataFormats/Candidate/interface/CandidateOnlyFwd.h"
 #include "DataFormats/TrackReco/interface/TrackFwd.h"
 #include "DataFormats/HLTReco/interface/TriggerFilterObjectWithRefs.h"
 #include "DataFormats/HLTReco/interface/TriggerRefsCollections.h"
@@ -31,10 +32,6 @@ namespace edm {
 
 // ----------------------------------------------------------------------
 
-namespace reco {
-  class Candidate;
-}  // namespace reco
-
 class FreeTrajectoryState;
 class MagneticField;
 
diff --git a/HeavyFlavorAnalysis/RecoDecay/interface/BPHDecayVertex.h b/HeavyFlavorAnalysis/RecoDecay/interface/BPHDecayVertex.h
index 985b0be23436f..04e8fbfe96804 100644
--- a/HeavyFlavorAnalysis/RecoDecay/interface/BPHDecayVertex.h
+++ b/HeavyFlavorAnalysis/RecoDecay/interface/BPHDecayVertex.h
@@ -13,6 +13,7 @@
 // Base Class Headers --
 //----------------------
 #include "HeavyFlavorAnalysis/RecoDecay/interface/BPHDecayMomentum.h"
+#include "DataFormats/VertexReco/interface/VertexFwd.h"
 
 class BPHEventSetupWrapper;
 
@@ -22,7 +23,6 @@ namespace edm {
 
 namespace reco {
   class TransientTrack;
-  class Vertex;
 }  // namespace reco
 
 //------------------------------------
diff --git a/HeavyFlavorAnalysis/RecoDecay/interface/BPHMultiSelect.h b/HeavyFlavorAnalysis/RecoDecay/interface/BPHMultiSelect.h
index af0dc79f55300..beffbf057feea 100644
--- a/HeavyFlavorAnalysis/RecoDecay/interface/BPHMultiSelect.h
+++ b/HeavyFlavorAnalysis/RecoDecay/interface/BPHMultiSelect.h
@@ -20,14 +20,12 @@
 #include "HeavyFlavorAnalysis/RecoDecay/interface/BPHMomentumSelect.h"
 #include "HeavyFlavorAnalysis/RecoDecay/interface/BPHVertexSelect.h"
 #include "HeavyFlavorAnalysis/RecoDecay/interface/BPHFitSelect.h"
+#include "DataFormats/Candidate/interface/CandidateOnlyFwd.h"
+
 class BPHRecoBuilder;
 class BPHDecayMomentum;
 class BPHDecayVertex;
 
-namespace reco {
-  class Candidate;
-}
-
 //---------------
 // C++ Headers --
 //---------------
diff --git a/HeavyFlavorAnalysis/RecoDecay/interface/BPHRecoCandidate.h b/HeavyFlavorAnalysis/RecoDecay/interface/BPHRecoCandidate.h
index a0fe7ccd5b2ec..c347d643e0b10 100644
--- a/HeavyFlavorAnalysis/RecoDecay/interface/BPHRecoCandidate.h
+++ b/HeavyFlavorAnalysis/RecoDecay/interface/BPHRecoCandidate.h
@@ -28,10 +28,6 @@
 
 class BPHEventSetupWrapper;
 
-namespace reco {
-  class Candidate;
-}
-
 //---------------
 // C++ Headers --
 //---------------
diff --git a/HeavyFlavorAnalysis/RecoDecay/interface/BPHRecoSelect.h b/HeavyFlavorAnalysis/RecoDecay/interface/BPHRecoSelect.h
index 73747a113763e..a0f42b70a330e 100644
--- a/HeavyFlavorAnalysis/RecoDecay/interface/BPHRecoSelect.h
+++ b/HeavyFlavorAnalysis/RecoDecay/interface/BPHRecoSelect.h
@@ -13,13 +13,11 @@
 // Base Class Headers --
 //----------------------
 #include "HeavyFlavorAnalysis/RecoDecay/interface/BPHRecoBuilder.h"
+#include "DataFormats/Candidate/interface/CandidateOnlyFwd.h"
 
 //------------------------------------
 // Collaborating Class Declarations --
 //------------------------------------
-namespace reco {
-  class Candidate;
-}
 
 //---------------
 // C++ Headers --
diff --git a/HeavyFlavorAnalysis/SpecificDecay/plugins/BPHHistoSpecificDecay.h b/HeavyFlavorAnalysis/SpecificDecay/plugins/BPHHistoSpecificDecay.h
index df54d6f7d6e43..a26204f6203a2 100644
--- a/HeavyFlavorAnalysis/SpecificDecay/plugins/BPHHistoSpecificDecay.h
+++ b/HeavyFlavorAnalysis/SpecificDecay/plugins/BPHHistoSpecificDecay.h
@@ -3,6 +3,7 @@
 
 #include "HeavyFlavorAnalysis/RecoDecay/interface/BPHAnalyzerTokenWrapper.h"
 #include "DataFormats/PatCandidates/interface/CompositeCandidate.h"
+#include "DataFormats/VertexReco/interface/VertexFwd.h"
 #include "DataFormats/Common/interface/TriggerResults.h"
 
 #include "FWCore/Framework/interface/Event.h"
@@ -20,11 +21,6 @@ class TTree;
 class TBranch;
 class TVector3;
 
-namespace reco {
-  class Candidate;
-  class Vertex;
-}  // namespace reco
-
 class BPHHistoSpecificDecay : public BPHAnalyzerWrapper<BPHModuleWrapper::one_analyzer> {
 public:
   explicit BPHHistoSpecificDecay(const edm::ParameterSet& ps);
diff --git a/PhysicsTools/Heppy/interface/EGammaMvaEleEstimatorFWLite.h b/PhysicsTools/Heppy/interface/EGammaMvaEleEstimatorFWLite.h
index ff7731029abc5..8d4ce2f1d505d 100644
--- a/PhysicsTools/Heppy/interface/EGammaMvaEleEstimatorFWLite.h
+++ b/PhysicsTools/Heppy/interface/EGammaMvaEleEstimatorFWLite.h
@@ -3,9 +3,7 @@
 
 class EGammaMvaEleEstimator;
 class EGammaMvaEleEstimatorCSA14;
-namespace reco {
-  class Vertex;
-}
+#include "DataFormats/VertexReco/interface/VertexFwd.h"
 namespace pat {
   class Electron;
 }
diff --git a/PhysicsTools/ONNXRuntime/test/BuildFile.xml b/PhysicsTools/ONNXRuntime/test/BuildFile.xml
index cb02c30d2f9c9..cb22286c89d1b 100644
--- a/PhysicsTools/ONNXRuntime/test/BuildFile.xml
+++ b/PhysicsTools/ONNXRuntime/test/BuildFile.xml
@@ -1,9 +1,13 @@
 <test name="test_py_onnxruntime" command="plot_load_and_predict.py">
   <use name="onnxruntime"/>
 </test>
+
+<iftool name="cuda">
+  <flags CPPDEFINES="CMSSW_CUDA_IS_AVAILABLE"/>
+</iftool>
 <bin name="testONNXRuntime" file="testRunner.cpp, testONNXRuntime.cc">
   <use name="cppunit"/>
-  <use name="PhysicsTools/ONNXRuntime"/>
-  <use name="HeterogeneousCore/CUDAUtilities"/>
   <use name="FWCore/ParameterSet"/>
+  <use name="HeterogeneousCore/CUDAUtilities"/>
+  <use name="PhysicsTools/ONNXRuntime"/>
 </bin>
diff --git a/PhysicsTools/ONNXRuntime/test/testONNXRuntime.cc b/PhysicsTools/ONNXRuntime/test/testONNXRuntime.cc
index 29ed226f6acc0..0f250c2d6105f 100644
--- a/PhysicsTools/ONNXRuntime/test/testONNXRuntime.cc
+++ b/PhysicsTools/ONNXRuntime/test/testONNXRuntime.cc
@@ -2,7 +2,9 @@
 
 #include "PhysicsTools/ONNXRuntime/interface/ONNXRuntime.h"
 #include "FWCore/ParameterSet/interface/FileInPath.h"
+#ifdef CMSSW_CUDA_IS_AVAILABLE
 #include "HeterogeneousCore/CUDAUtilities/interface/requireDevices.h"
+#endif
 
 #include <iostream>
 
@@ -11,7 +13,9 @@ using namespace cms::Ort;
 class testONNXRuntime : public CppUnit::TestFixture {
   CPPUNIT_TEST_SUITE(testONNXRuntime);
   CPPUNIT_TEST(checkCPU);
+#ifdef CMSSW_CUDA_IS_AVAILABLE
   CPPUNIT_TEST(checkGPU);
+#endif
   CPPUNIT_TEST_SUITE_END();
 
 private:
@@ -45,7 +49,9 @@ void testONNXRuntime::test(Backend backend) {
 void testONNXRuntime::checkCPU() { test(Backend::cpu); }
 
 void testONNXRuntime::checkGPU() {
+#ifdef CMSSW_CUDA_IS_AVAILABLE
   if (cms::cudatest::testDevices()) {
     test(Backend::cuda);
   }
+#endif
 }
diff --git a/PhysicsTools/PatAlgos/interface/KinematicResolutionProvider.h b/PhysicsTools/PatAlgos/interface/KinematicResolutionProvider.h
index edbec4e2c5b49..922d078f10225 100644
--- a/PhysicsTools/PatAlgos/interface/KinematicResolutionProvider.h
+++ b/PhysicsTools/PatAlgos/interface/KinematicResolutionProvider.h
@@ -14,10 +14,8 @@
 
    a setup function is provided but might need to be re-implemented. 
 */
+#include "DataFormats/Candidate/interface/CandidateOnlyFwd.h"
 
-namespace reco {
-  class Candidate;
-}
 namespace pat {
   class CandKinResolution;
 }
diff --git a/PhysicsTools/RecoUtils/interface/CandCommonVertexFitter.h b/PhysicsTools/RecoUtils/interface/CandCommonVertexFitter.h
index 52a5c3dfcf55f..24b7aff445792 100644
--- a/PhysicsTools/RecoUtils/interface/CandCommonVertexFitter.h
+++ b/PhysicsTools/RecoUtils/interface/CandCommonVertexFitter.h
@@ -10,11 +10,9 @@
 #include "TrackingTools/TransientTrack/interface/TransientTrack.h"
 #include "RecoVertex/VertexPrimitives/interface/TransientVertex.h"
 #include "DataFormats/RecoCandidate/interface/RecoCandidate.h"
+#include "DataFormats/Candidate/interface/VertexCompositeCandidateOnlyFwd.h"
 #include <vector>
 class MagneticField;
-namespace reco {
-  class VertexCompositeCandidate;
-}
 
 class CandCommonVertexFitterBase {
 public:
diff --git a/PhysicsTools/RecoUtils/interface/CandKinematicVertexFitter.h b/PhysicsTools/RecoUtils/interface/CandKinematicVertexFitter.h
index c91c2c59927d6..948c3074415b6 100644
--- a/PhysicsTools/RecoUtils/interface/CandKinematicVertexFitter.h
+++ b/PhysicsTools/RecoUtils/interface/CandKinematicVertexFitter.h
@@ -10,6 +10,7 @@
 #include "TrackingTools/TransientTrack/interface/TransientTrack.h"
 #include "RecoVertex/VertexPrimitives/interface/TransientVertex.h"
 #include "DataFormats/RecoCandidate/interface/RecoCandidate.h"
+#include "DataFormats/Candidate/interface/VertexCompositeCandidateOnlyFwd.h"
 #include "RecoVertex/KinematicFit/interface/KinematicParticleVertexFitter.h"
 #include "PhysicsTools/UtilAlgos/interface/ParameterAdapter.h"
 #include "RecoVertex/KinematicFitPrimitives/interface/KinematicParticleFactoryFromTransientTrack.h"
@@ -17,9 +18,6 @@
 #include <vector>
 
 class MagneticField;
-namespace reco {
-  class VertexCompositeCandidate;
-}
 
 class CandKinematicVertexFitter {
 public:
diff --git a/RecoEgamma/EgammaElectronAlgos/interface/ecalClusterEnergyUncertaintyElectronSpecific.h b/RecoEgamma/EgammaElectronAlgos/interface/ecalClusterEnergyUncertaintyElectronSpecific.h
index 6c861c73cb454..cb3c6f0f54039 100644
--- a/RecoEgamma/EgammaElectronAlgos/interface/ecalClusterEnergyUncertaintyElectronSpecific.h
+++ b/RecoEgamma/EgammaElectronAlgos/interface/ecalClusterEnergyUncertaintyElectronSpecific.h
@@ -12,9 +12,7 @@
   *  \author Nicolas Chanon, December 2011
   */
 
-namespace reco {
-  class SuperCluster;
-}
+#include "DataFormats/EgammaReco/interface/SuperClusterFwd.h"
 
 namespace egamma {
 
diff --git a/RecoEgamma/EgammaElectronProducers/plugins/LowPtGsfElectronSeedHeavyObjectCache.h b/RecoEgamma/EgammaElectronProducers/plugins/LowPtGsfElectronSeedHeavyObjectCache.h
index 5baeb06472f65..2443afb1cdf9a 100644
--- a/RecoEgamma/EgammaElectronProducers/plugins/LowPtGsfElectronSeedHeavyObjectCache.h
+++ b/RecoEgamma/EgammaElectronProducers/plugins/LowPtGsfElectronSeedHeavyObjectCache.h
@@ -2,15 +2,12 @@
 #define RecoEgamma_EgammaElectronProducers_LowPtGsfElectronSeedHeavyObjectCache_h
 
 #include "CondFormats/GBRForest/interface/GBRForest.h"
+#include "DataFormats/BeamSpot/interface/BeamSpotFwd.h"
+#include "DataFormats/ParticleFlowReco/interface/PreIdFwd.h"
 #include "FWCore/ParameterSet/interface/ParameterSet.h"
 #include "RecoEcal/EgammaCoreTools/interface/EcalClusterLazyTools.h"
 #include <vector>
 
-namespace reco {
-  class BeamSpot;
-  class PreId;
-}  // namespace reco
-
 namespace lowptgsfeleseed {
 
   class HeavyObjectCache {
diff --git a/RecoEgamma/EgammaTools/interface/AnyMVAEstimatorRun2Base.h b/RecoEgamma/EgammaTools/interface/AnyMVAEstimatorRun2Base.h
index 09b44faaad39d..fcbc494e6b378 100644
--- a/RecoEgamma/EgammaTools/interface/AnyMVAEstimatorRun2Base.h
+++ b/RecoEgamma/EgammaTools/interface/AnyMVAEstimatorRun2Base.h
@@ -8,15 +8,12 @@
 
 #include <string>
 #include <vector>
+#include "DataFormats/Candidate/interface/CandidateOnlyFwd.h"
 
 namespace edm {
   class ParameterSet;
 }  // namespace edm
 
-namespace reco {
-  class Candidate;
-}  // namespace reco
-
 class AnyMVAEstimatorRun2Base {
 public:
   // Constructor, destructor
diff --git a/RecoEgamma/EgammaTools/interface/EcalRegressionData.h b/RecoEgamma/EgammaTools/interface/EcalRegressionData.h
index 986dac2e2ef85..ba18c4d017831 100644
--- a/RecoEgamma/EgammaTools/interface/EcalRegressionData.h
+++ b/RecoEgamma/EgammaTools/interface/EcalRegressionData.h
@@ -4,16 +4,13 @@
 #include "DataFormats/EcalRecHit/interface/EcalRecHitCollections.h"
 #include "DataFormats/VertexReco/interface/VertexFwd.h"
 #include "DataFormats/VertexReco/interface/Vertex.h"
+#include "DataFormats/EgammaReco/interface/SuperClusterFwd.h"
 #include <vector>
 #include <cmath>
 
 class CaloGeometry;
 class CaloTopology;
 
-namespace reco {
-  class SuperCluster;
-}
-
 class EcalRegressionData {
 public:
   EcalRegressionData() { clear(); }
diff --git a/RecoEgamma/EgammaTools/interface/EpCombinationTool.h b/RecoEgamma/EgammaTools/interface/EpCombinationTool.h
index 52a9c6b1c64a7..ebfe438f7df41 100644
--- a/RecoEgamma/EgammaTools/interface/EpCombinationTool.h
+++ b/RecoEgamma/EgammaTools/interface/EpCombinationTool.h
@@ -2,6 +2,7 @@
 #define RecoEgamma_EgammaTools_EpCombinationTool_h
 
 #include "RecoEgamma/EgammaTools/interface/EgammaRegressionContainer.h"
+#include "DataFormats/EgammaCandidates/interface/GsfElectronFwd.h"
 
 #include <string>
 #include <vector>
@@ -13,9 +14,6 @@ namespace edm {
   class EventSetup;
   class ConsumesCollector;
 }  // namespace edm
-namespace reco {
-  class GsfElectron;
-}
 
 class EpCombinationTool {
 public:
diff --git a/RecoEgamma/ElectronIdentification/interface/ElectronMVAEstimatorRun2.h b/RecoEgamma/ElectronIdentification/interface/ElectronMVAEstimatorRun2.h
index 9a94e12b07562..ad34ce72093f3 100644
--- a/RecoEgamma/ElectronIdentification/interface/ElectronMVAEstimatorRun2.h
+++ b/RecoEgamma/ElectronIdentification/interface/ElectronMVAEstimatorRun2.h
@@ -6,6 +6,7 @@
 #include "CondFormats/GBRForest/interface/GBRForest.h"
 #include "RecoEgamma/EgammaTools/interface/AnyMVAEstimatorRun2Base.h"
 #include "RecoEgamma/EgammaTools/interface/MVAVariableManager.h"
+#include "DataFormats/EgammaCandidates/interface/GsfElectronFwd.h"
 
 // Note on Python/FWLite support:
 //
@@ -25,10 +26,6 @@
 // C++ modules, we try to forwar declare as much as possible in
 // ElectronMVAEstimatorRun2.h and AnyMVAEstimatorRun2Base.h.
 
-namespace reco {
-  class GsfElectron;
-}
-
 class ElectronMVAEstimatorRun2 : public AnyMVAEstimatorRun2Base {
 public:
   // Constructor
diff --git a/RecoHGCal/TICL/plugins/ClusterFilterBase.h b/RecoHGCal/TICL/plugins/ClusterFilterBase.h
index 46ed3ebd93e49..1aa8aacdf5c6f 100644
--- a/RecoHGCal/TICL/plugins/ClusterFilterBase.h
+++ b/RecoHGCal/TICL/plugins/ClusterFilterBase.h
@@ -5,6 +5,7 @@
 #define RecoHGCal_TICL_ClusterFilterBase_H__
 
 #include "DataFormats/HGCalReco/interface/Common.h"
+#include "DataFormats/CaloRecHit/interface/CaloClusterFwd.h"
 #include "RecoLocalCalo/HGCalRecAlgos/interface/RecHitTools.h"
 
 #include <memory>
@@ -13,10 +14,6 @@
 namespace edm {
   class ParameterSet;
 }
-namespace reco {
-  class CaloCluster;
-}
-
 namespace ticl {
   class ClusterFilterBase {
   public:
diff --git a/RecoHI/HiTracking/interface/HIProtoTrackFilter.h b/RecoHI/HiTracking/interface/HIProtoTrackFilter.h
index fe441ef46b9e6..843cdee51c801 100644
--- a/RecoHI/HiTracking/interface/HIProtoTrackFilter.h
+++ b/RecoHI/HiTracking/interface/HIProtoTrackFilter.h
@@ -2,10 +2,7 @@
 #define _HIProtoTrackFilter_h_
 
 #include "RecoTracker/PixelTrackFitting/interface/PixelTrackFilterBase.h"
-
-namespace reco {
-  class BeamSpot;
-}
+#include "DataFormats/BeamSpot/interface/BeamSpotFwd.h"
 
 class HIProtoTrackFilter : public PixelTrackFilterBase {
 public:
diff --git a/RecoJets/JetProducers/interface/JetMatchingTools.h b/RecoJets/JetProducers/interface/JetMatchingTools.h
index d82df6d09eced..52d8a61b434eb 100644
--- a/RecoJets/JetProducers/interface/JetMatchingTools.h
+++ b/RecoJets/JetProducers/interface/JetMatchingTools.h
@@ -10,15 +10,13 @@
 #include "SimDataFormats/Vertex/interface/SimVertexContainer.h"
 #include "SimDataFormats/Track/interface/SimTrackContainer.h"
 #include "DataFormats/HepMCCandidate/interface/GenParticle.h"
+#include "DataFormats/JetReco/interface/CaloJetFwd.h"
+#include "DataFormats/JetReco/interface/GenJetFwd.h"
 #include "FWCore/Framework/interface/ConsumesCollector.h"
 
 namespace edm {
   class Event;
 }
-namespace reco {
-  class CaloJet;
-  class GenJet;
-}  // namespace reco
 
 class CaloTower;
 class CaloRecHit;
diff --git a/RecoMuon/MuonIdentification/interface/MuonShowerInformationFiller.h b/RecoMuon/MuonIdentification/interface/MuonShowerInformationFiller.h
index 3141e2116b891..fa255bc4118c7 100644
--- a/RecoMuon/MuonIdentification/interface/MuonShowerInformationFiller.h
+++ b/RecoMuon/MuonIdentification/interface/MuonShowerInformationFiller.h
@@ -46,7 +46,6 @@ namespace edm {
 }  // namespace edm
 namespace reco {
   class TransientTrack;
-  struct MuonShower;
 }  // namespace reco
 
 class MuonServiceProxy;
diff --git a/RecoTauTag/RecoTau/interface/PFRecoTauChargedHadronPlugins.h b/RecoTauTag/RecoTau/interface/PFRecoTauChargedHadronPlugins.h
index 9aecb72f0e746..88337a577d1c9 100644
--- a/RecoTauTag/RecoTau/interface/PFRecoTauChargedHadronPlugins.h
+++ b/RecoTauTag/RecoTau/interface/PFRecoTauChargedHadronPlugins.h
@@ -18,6 +18,7 @@
  */
 
 #include "DataFormats/ParticleFlowCandidate/interface/PFCandidateFwd.h"
+#include "DataFormats/JetReco/interface/JetFwd.h"
 #include "FWCore/Framework/interface/ConsumesCollector.h"
 #include "RecoTauTag/RecoTau/interface/RecoTauPluginsCommon.h"
 
@@ -26,7 +27,6 @@
 namespace reco {
 
   // Forward declarations
-  class Jet;
   class PFRecoTauChargedHadron;
 
   namespace tau {
diff --git a/RecoTauTag/RecoTau/interface/PFTauDecayModeTools.h b/RecoTauTag/RecoTau/interface/PFTauDecayModeTools.h
index 9546be96d1aa2..cdf03bb2d7403 100644
--- a/RecoTauTag/RecoTau/interface/PFTauDecayModeTools.h
+++ b/RecoTauTag/RecoTau/interface/PFTauDecayModeTools.h
@@ -10,11 +10,7 @@
  */
 
 #include "DataFormats/TauReco/interface/PFTau.h"
-
-// Forward declaration
-namespace reco {
-  class GenJet;
-}
+#include "DataFormats/JetReco/interface/GenJetFwd.h"
 
 namespace reco {
   namespace tau {
diff --git a/RecoTauTag/RecoTau/interface/RecoTauPiZeroPlugins.h b/RecoTauTag/RecoTau/interface/RecoTauPiZeroPlugins.h
index 19ad4107ff680..e8b58714b0748 100644
--- a/RecoTauTag/RecoTau/interface/RecoTauPiZeroPlugins.h
+++ b/RecoTauTag/RecoTau/interface/RecoTauPiZeroPlugins.h
@@ -19,14 +19,13 @@
 
 #include <vector>
 #include "DataFormats/ParticleFlowCandidate/interface/PFCandidateFwd.h"
+#include "DataFormats/JetReco/interface/JetFwd.h"
 #include "RecoTauTag/RecoTau/interface/RecoTauPluginsCommon.h"
+#include "DataFormats/TauReco/interface/RecoTauPiZeroFwd.h"
 
 #include "FWCore/Framework/interface/ConsumesCollector.h"
 
 namespace reco {
-  // Forward declarations
-  class Jet;
-  class RecoTauPiZero;
   namespace tau {
 
     class RecoTauPiZeroBuilderPlugin : public RecoTauEventHolderPlugin {
diff --git a/RecoTauTag/RecoTau/interface/RecoTauVertexAssociator.h b/RecoTauTag/RecoTau/interface/RecoTauVertexAssociator.h
index 08947019d920d..7ac50c57fe6ad 100644
--- a/RecoTauTag/RecoTau/interface/RecoTauVertexAssociator.h
+++ b/RecoTauTag/RecoTau/interface/RecoTauVertexAssociator.h
@@ -21,6 +21,8 @@
 #include "FWCore/Framework/interface/EDConsumerBase.h"
 #include "FWCore/Utilities/interface/InputTag.h"
 #include "DataFormats/VertexReco/interface/VertexFwd.h"
+#include "DataFormats/JetReco/interface/JetFwd.h"
+#include "DataFormats/TauReco/interface/PFTauFwd.h"
 #include "DataFormats/Common/interface/Handle.h"
 #include "RecoTauTag/RecoTau/interface/RecoTauQualityCuts.h"
 
@@ -39,11 +41,6 @@ namespace edm {
   class Event;
 }  // namespace edm
 
-namespace reco {
-  class PFTau;
-  class Jet;
-}  // namespace reco
-
 namespace reco {
   namespace tau {
 
diff --git a/RecoTracker/PixelTrackFitting/interface/KFBasedPixelFitter.h b/RecoTracker/PixelTrackFitting/interface/KFBasedPixelFitter.h
index fb90fc8224239..4f5832839615f 100644
--- a/RecoTracker/PixelTrackFitting/interface/KFBasedPixelFitter.h
+++ b/RecoTracker/PixelTrackFitting/interface/KFBasedPixelFitter.h
@@ -5,13 +5,10 @@
 #include "Geometry/CommonDetUnit/interface/GeomDet.h"
 #include "TrackingTools/TransientTrackingRecHit/interface/TValidTrackingRecHit.h"
 #include "DataFormats/TrackReco/interface/TrackFwd.h"
+#include "DataFormats/BeamSpot/interface/BeamSpotFwd.h"
 
 #include <vector>
 
-namespace reco {
-  class BeamSpot;
-}  // namespace reco
-
 class TransientTrackingRecHitBuilder;
 class TrackerGeometry;
 class MagneticField;
diff --git a/RecoVertex/BeamSpotProducer/interface/PVFitter.h b/RecoVertex/BeamSpotProducer/interface/PVFitter.h
index 71d019d9f8d4e..a2f1c4905031e 100644
--- a/RecoVertex/BeamSpotProducer/interface/PVFitter.h
+++ b/RecoVertex/BeamSpotProducer/interface/PVFitter.h
@@ -38,10 +38,6 @@ namespace edm {
   class ConsumesCollector;
 }
 
-namespace reco {
-  class Vertex;
-}
-
 class PVFitter {
 public:
   PVFitter() {}
diff --git a/RecoVertex/PrimaryVertexProducer/interface/PrimaryVertexFitterBase.h b/RecoVertex/PrimaryVertexProducer/interface/PrimaryVertexFitterBase.h
index 870654e2766df..023835ce4c533 100644
--- a/RecoVertex/PrimaryVertexProducer/interface/PrimaryVertexFitterBase.h
+++ b/RecoVertex/PrimaryVertexProducer/interface/PrimaryVertexFitterBase.h
@@ -2,6 +2,7 @@
 #define PrimaryVertexFitterBase_h
 
 #include <vector>
+#include "DataFormats/BeamSpot/interface/BeamSpotFwd.h"
 
 /**\class PrimaryVertexFitterBase
  
@@ -14,7 +15,6 @@ namespace edm {
 }  // namespace edm
 
 namespace reco {
-  class BeamSpot;
   class TransientTrack;
 }  // namespace reco
 
diff --git a/SimGeneral/DataMixingModule/plugins/DataMixingPileupCopy.h b/SimGeneral/DataMixingModule/plugins/DataMixingPileupCopy.h
index 84f70fecec45a..a1c4c06a264b6 100644
--- a/SimGeneral/DataMixingModule/plugins/DataMixingPileupCopy.h
+++ b/SimGeneral/DataMixingModule/plugins/DataMixingPileupCopy.h
@@ -25,15 +25,12 @@
 
 #include "SimDataFormats/CrossingFrame/interface/CrossingFramePlaybackInfoNew.h"
 #include "SimDataFormats/PileupSummaryInfo/interface/PileupSummaryInfo.h"
+#include "DataFormats/HepMCCandidate/interface/GenParticleFwd.h"
 
 #include <map>
 #include <string>
 #include <vector>
 
-namespace reco {
-  class GenParticle;
-}
-
 namespace edm {
   class ModuleCallingContext;
 
diff --git a/SimGeneral/PreMixingModule/plugins/PreMixingPileupCopy.h b/SimGeneral/PreMixingModule/plugins/PreMixingPileupCopy.h
index 14ee046b772ec..d4b152c76a0e9 100644
--- a/SimGeneral/PreMixingModule/plugins/PreMixingPileupCopy.h
+++ b/SimGeneral/PreMixingModule/plugins/PreMixingPileupCopy.h
@@ -16,6 +16,7 @@
 
 #include "DataFormats/Provenance/interface/ProductID.h"
 #include "DataFormats/Common/interface/Handle.h"
+#include "DataFormats/HepMCCandidate/interface/GenParticleFwd.h"
 
 #include "SimDataFormats/PileupSummaryInfo/interface/PileupSummaryInfo.h"
 #include "SimDataFormats/CrossingFrame/interface/CrossingFramePlaybackInfoNew.h"
@@ -23,9 +24,6 @@
 #include <vector>
 #include <string>
 
-namespace reco {
-  class GenParticle;
-}
 class PileUpEventPrincipal;
 
 namespace edm {
diff --git a/TrackingTools/GeomPropagators/interface/Propagator.h b/TrackingTools/GeomPropagators/interface/Propagator.h
index 45022e2df522a..364056533ab91 100644
--- a/TrackingTools/GeomPropagators/interface/Propagator.h
+++ b/TrackingTools/GeomPropagators/interface/Propagator.h
@@ -2,6 +2,7 @@
 #define CommonDet_Propagator_H
 
 #include "DataFormats/TrajectorySeed/interface/PropagationDirection.h"
+#include "DataFormats/BeamSpot/interface/BeamSpotFwd.h"
 #include "TrackingTools/TrajectoryState/interface/FreeTrajectoryState.h"
 #include "TrackingTools/TrajectoryState/interface/TrajectoryStateOnSurface.h"
 
@@ -13,10 +14,6 @@ class Cylinder;
 class Surface;
 class MagneticField;
 
-namespace reco {
-  class BeamSpot;
-}
-
 /** Basic tool for "propagation" of trajectory states to surfaces.
  *  If the starting state has an error matrix the errors will be also
  *  propagated. If you want to propagate just the parameters,
diff --git a/Validation/HGCalValidation/scripts/testHGCalCellHitSum_cfg.py b/Validation/HGCalValidation/scripts/testHGCalCellHitSum_cfg.py
index fad35c65b6ecb..dac1f679a6746 100644
--- a/Validation/HGCalValidation/scripts/testHGCalCellHitSum_cfg.py
+++ b/Validation/HGCalValidation/scripts/testHGCalCellHitSum_cfg.py
@@ -2,13 +2,13 @@
 # Way to use this:
 #   cmsRun testHGCalCellHitSum_cfg.py geometry=D121 layers=1 type=mu
 #
-#   Options for geometry D105, D110, D114
+#   Options for geometry D104, D110, D114, D121
 #               layers '1', '1,2', any combination from 1..47           
 #               type mu, tt
 #
 ###############################################################################
 import FWCore.ParameterSet.Config as cms
-import os, sys, imp, re
+import os, sys, re
 import FWCore.ParameterSet.VarParsing as VarParsing
 
 ####################################################################
@@ -18,7 +18,7 @@
                  "D121",
                   VarParsing.VarParsing.multiplicity.singleton,
                   VarParsing.VarParsing.varType.string,
-                  "geometry of operations: D105, D114, D121")
+                  "geometry of operations: D104, D110, D114, D121")
 
 options.register('layers',
                  "1",
@@ -35,30 +35,33 @@
 ### get and parse the command line arguments
 options.parseArguments()
 
-import FWCore.ParameterSet.Config as cms
-from Configuration.Eras.Era_Phase2C17I13M9_cff import Phase2C17I13M9
-process = cms.Process('HGCalCellHit',Phase2C17I13M9)
+geomName = "Run4" + options.geometry
+loadFile = "Configuration.Geometry.GeometryExtended" + geomName + "Reco_cff"
+import Configuration.Geometry.defaultPhase2ConditionsEra_cff as _settings
+GLOBAL_TAG, ERA = _settings.get_era_and_conditions(geomName)
+
+process = cms.Process('HGCalCellHit',ERA)
 
 print(options)
 
 ####################################################################
 # Use the options
 
-loadFile = "Configuration.Geometry.GeometryExtendedRun4" + options.geometry + "Reco_cff"
 inputFile = "file:step1" + options.geometry + options.type + ".root"
 outputFile = "file:geantoutput" + options.geometry + options.type + ".root"
 
-if (options.geometry == "D105"):
-    geomFile = 'Validation/HGCalValidation/data/wafer_v16.csv'
-elif (options.geometry == "D114"):
+if (options.geometry == "D114"):
     geomFile = 'Validation/HGCalValidation/data/wafer_v17.csv'
 else:
     geomFile = 'Validation/HGCalValidation/data/wafer_v17.csv'
 
-print("Geometry file: ", loadFile)
-print("Wafer file:    ", geomFile)
-print("Input file:    ", inputFile)
-print("Output file:   ", outputFile)
+print("Geometry Name:   ", geomName)
+print("Geometry file:   ", loadFile)
+print("Wafer file:      ", geomFile)
+print("Input file:      ", inputFile)
+print("Output file:     ", outputFile)
+print("Global Tag Name: ", GLOBAL_TAG)
+print("Era Name:        ", ERA)
 
 process.load('SimGeneral.HepPDTESSource.pythiapdt_cfi')
 process.load(loadFile)
diff --git a/Validation/HGCalValidation/scripts/testHGCalDigi_cfg.py b/Validation/HGCalValidation/scripts/testHGCalDigi_cfg.py
index 98edab1f74528..868d2c7c5b8fc 100644
--- a/Validation/HGCalValidation/scripts/testHGCalDigi_cfg.py
+++ b/Validation/HGCalValidation/scripts/testHGCalDigi_cfg.py
@@ -3,7 +3,7 @@
 #   cmsRun testHGCalDigi_cfg.py geometry=D111 type=DDD data=mu noise=none
 #                               threshold=none
 #
-#   Options for geometry: D105, D111, D114, V17Shift, D104
+#   Options for geometry: D121, D111, D114, V17Shift, D104
 #               type: DDD, DD4hep
 #               data: mu, tt
 #               noise: none, ok
@@ -18,10 +18,10 @@
 ### SETUP OPTIONS
 options = VarParsing.VarParsing('standard')
 options.register('geometry',
-                 "D111",
+                 "D121",
                   VarParsing.VarParsing.multiplicity.singleton,
                   VarParsing.VarParsing.varType.string,
-                  "geometry of operations: D105, D111, D114, V17Shift, D104")
+                  "geometry of operations: D121, D111, D114, V17Shift, D104")
 options.register('type',
                  "DDD",
                   VarParsing.VarParsing.multiplicity.singleton,
diff --git a/Validation/HGCalValidation/scripts/testHGCalMTRecoStudy_cfg.py b/Validation/HGCalValidation/scripts/testHGCalMTRecoStudy_cfg.py
index 1fd1eb411b084..2bef04a88e386 100644
--- a/Validation/HGCalValidation/scripts/testHGCalMTRecoStudy_cfg.py
+++ b/Validation/HGCalValidation/scripts/testHGCalMTRecoStudy_cfg.py
@@ -2,7 +2,7 @@
 # Way to use this:
 #   cmsRun runHGCalRecHitStudy_cfg.py geometry=D121
 #
-#   Options for geometry D105, D114,D120, D121
+#   Options for geometry D114, D120, D121
 #
 ###############################################################################
 import FWCore.ParameterSet.Config as cms
@@ -19,7 +19,7 @@
                  "D121",
                   VarParsing.VarParsing.multiplicity.singleton,
                   VarParsing.VarParsing.varType.string,
-                  "geometry of operations: D105, D114, D121")
+                  "geometry of operations: D110, D114, D121")
 
 options.register('layers',
                  "1",
@@ -39,23 +39,23 @@
 
 fileInput = "file:step3.root"
 
-if (options.geometry == "D105"):
-    from Configuration.Eras.Era_Phase2C17I13M9_cff import Phase2C17I13M9
-    process = cms.Process('HGCalMTReco',Phase2C17I13M9)
-    process.load('Configuration.Geometry.GeometryExtendedRun4D105Reco_cff')
-    outputFile = 'file:recoutputD105.root'
-elif (options.geometry == "D114"):
+if (options.geometry == "D114"):
     from Configuration.Eras.Era_Phase2C17I13M9_cff import Phase2C17I13M9
     process = cms.Process('HGCalMTReco',Phase2C17I13M9)
     process.load('Configuration.Geometry.GeometryExtendedRun4D114Reco_cff')
     outputFile = 'file:recoutputD114.root'
+elif (options.geometry == "D110"):
+    from Configuration.Eras.Era_Phase2C22I13M9_cff import Phase2C22I13M9
+    process = cms.Process('HGCalMTReco',Phase2C22I13M9)
+    process.load('Configuration.Geometry.GeometryExtendedRun4D110Reco_cff')
+    outputFile = 'file:recoutputD110.root'
 elif (options.geometry == "D121"):
     from Configuration.Eras.Era_Phase2C22I13M9_cff import Phase2C22I13M9
     process = cms.Process('HGCalMTReco',Phase2C22I13M9)
     process.load('Configuration.Geometry.GeometryExtendedRun4D121Reco_cff')
     outputFile = 'file:recoutputD121.root'
 else:
-    print("Please select a valid geometry version e.g. D105, D114, D121....")
+    print("Please select a valid geometry version e.g. D110, D114, D121....")
 
 print("Input file: ", fileInput)
 print("Output file: ", outputFile)
diff --git a/Validation/HGCalValidation/scripts/testHGCalReco_cfg.py b/Validation/HGCalValidation/scripts/testHGCalReco_cfg.py
index ca542a56d42ff..13fd1978c86ba 100644
--- a/Validation/HGCalValidation/scripts/testHGCalReco_cfg.py
+++ b/Validation/HGCalValidation/scripts/testHGCalReco_cfg.py
@@ -2,7 +2,7 @@
 # Way to use this:
 #   cmsRun testHGCalDigi_cfg.py geometry=D121 type=DDD data=mu tag=Def
 #
-#   Options for geometry: D105, D114, V17Shift, D104, D121
+#   Options for geometry: D110, D114, V17Shift, D104, D121
 #               type: DDD, DD4hep
 #               data: mu, tt
 #               tag: Def, Thr, 0Noise
@@ -19,7 +19,7 @@
                  "D121",
                   VarParsing.VarParsing.multiplicity.singleton,
                   VarParsing.VarParsing.varType.string,
-                  "geometry of operations: D105, D121, D114, V17Shift, D104")
+                  "geometry of operations: D110, D121, D114, V17Shift, D104")
 options.register('type',
                  "DDD",
                   VarParsing.VarParsing.multiplicity.singleton,
diff --git a/Validation/HGCalValidation/scripts/testHGCalSimSingleMuonPt100_cfg.py b/Validation/HGCalValidation/scripts/testHGCalSimSingleMuonPt100_cfg.py
index 120ee9b32414d..4ade9ce18307b 100644
--- a/Validation/HGCalValidation/scripts/testHGCalSimSingleMuonPt100_cfg.py
+++ b/Validation/HGCalValidation/scripts/testHGCalSimSingleMuonPt100_cfg.py
@@ -2,7 +2,7 @@
 # Way to use this:
 #   cmsRun testHGCalSingleMuonPt100_cfg.py geometry=D110 type=DDD
 #
-#   Options for geometry: D105, D121, D114, V17Shift, D104
+#   Options for geometry: D110, D121, D114, V17Shift, D104
 #               type: DDD, DD4hep
 #
 ###############################################################################
@@ -17,7 +17,7 @@
                  "D121",
                   VarParsing.VarParsing.multiplicity.singleton,
                   VarParsing.VarParsing.varType.string,
-                  "geometry of operations: D105, D121, D114, V17Shift, D104")
+                  "geometry of operations: D110, D121, D114, V17Shift, D104")
 options.register('type',
                  "DDD",
                   VarParsing.VarParsing.multiplicity.singleton,
diff --git a/Validation/HGCalValidation/scripts/testHGCalSimTTBar_cfg.py b/Validation/HGCalValidation/scripts/testHGCalSimTTBar_cfg.py
index b41cdd5ca4a78..4f8d195d96d61 100644
--- a/Validation/HGCalValidation/scripts/testHGCalSimTTBar_cfg.py
+++ b/Validation/HGCalValidation/scripts/testHGCalSimTTBar_cfg.py
@@ -2,7 +2,7 @@
 # Way to use this:
 #   cmsRun testHGCalTTBar_cfg.py geometry=D110 type=DDD
 #
-#   Options for geometry: D105, D121, D114, V17Shift, D104
+#   Options for geometry: D110, D121, D114, V17Shift, D104
 #               type: DDD, DD4hep
 #
 ###############################################################################
@@ -17,7 +17,7 @@
                  "D121",
                   VarParsing.VarParsing.multiplicity.singleton,
                   VarParsing.VarParsing.varType.string,
-                  "geometry of operations: D105, D121, D114, V17Shift, D104")
+                  "geometry of operations: D110, D121, D114, V17Shift, D104")
 options.register('type',
                  "DDD",
                   VarParsing.VarParsing.multiplicity.singleton,
diff --git a/Validation/RecoEgamma/plugins/ElectronConversionRejectionValidator.h b/Validation/RecoEgamma/plugins/ElectronConversionRejectionValidator.h
index f60cacbd21947..608e4029f124b 100644
--- a/Validation/RecoEgamma/plugins/ElectronConversionRejectionValidator.h
+++ b/Validation/RecoEgamma/plugins/ElectronConversionRejectionValidator.h
@@ -8,6 +8,7 @@
 #include "DataFormats/Common/interface/RefVector.h"
 #include "DataFormats/VertexReco/interface/VertexFwd.h"
 #include "DataFormats/VertexReco/interface/Vertex.h"
+#include "DataFormats/BeamSpot/interface/BeamSpotFwd.h"
 #include "DataFormats/EgammaCandidates/interface/GsfElectronFwd.h"
 #include "DataFormats/EgammaCandidates/interface/ConversionFwd.h"
 //
@@ -21,9 +22,6 @@
 #include <vector>
 
 // forward declarations
-namespace reco {
-  class BeamSpot;
-}
 class TFile;
 class TH1F;
 class TH2F;
diff --git a/Validation/RecoEgamma/plugins/ElectronMcSignalValidator.h b/Validation/RecoEgamma/plugins/ElectronMcSignalValidator.h
index cab6a02eac806..9be73ef761d74 100644
--- a/Validation/RecoEgamma/plugins/ElectronMcSignalValidator.h
+++ b/Validation/RecoEgamma/plugins/ElectronMcSignalValidator.h
@@ -17,10 +17,7 @@ class MagneticField;
 #include "DataFormats/Common/interface/ValueMap.h"
 #include "DataFormats/VertexReco/interface/Vertex.h"
 #include "DataFormats/VertexReco/interface/VertexFwd.h"
-
-namespace reco {
-  class BeamSpot;
-}
+#include "DataFormats/BeamSpot/interface/BeamSpotFwd.h"
 
 class ElectronMcSignalValidator : public ElectronDqmAnalyzerBase {
 public:
diff --git a/Validation/RecoTrack/interface/MultiTrackValidator.h b/Validation/RecoTrack/interface/MultiTrackValidator.h
index 42faf8661a856..505320203a3fe 100644
--- a/Validation/RecoTrack/interface/MultiTrackValidator.h
+++ b/Validation/RecoTrack/interface/MultiTrackValidator.h
@@ -24,11 +24,9 @@
 #include "CommonTools/Utils/interface/DynArray.h"
 #include "DataFormats/Common/interface/ValueMap.h"
 #include "DataFormats/Candidate/interface/Candidate.h"
+#include "DataFormats/TrackReco/interface/DeDxData.h"
 
 class PileupSummaryInfo;
-namespace reco {
-  class DeDxData;
-}
 
 struct MultiTrackValidatorHistograms {
   MTVHistoProducerAlgoForTrackerHistograms histoProducerAlgo;
diff --git a/Validation/RecoVertex/interface/BSvsPVHistogramMaker.h b/Validation/RecoVertex/interface/BSvsPVHistogramMaker.h
index ddca8c2eb6195..7207f675799f7 100644
--- a/Validation/RecoVertex/interface/BSvsPVHistogramMaker.h
+++ b/Validation/RecoVertex/interface/BSvsPVHistogramMaker.h
@@ -4,18 +4,14 @@
 #include <string>
 #include "FWCore/Framework/interface/ConsumesCollector.h"
 #include "DataFormats/VertexReco/interface/VertexFwd.h"
+#include "DataFormats/BeamSpot/interface/BeamSpotFwd.h"
 #include "FWCore/ParameterSet/interface/ParameterSet.h"
 #include "DPGAnalysis/SiStripTools/interface/RunHistogramManager.h"
 
 namespace edm {
-  class ParameterSet;
   class Event;
 }  // namespace edm
 
-namespace reco {
-  class BeamSpot;
-}
-
 class TH1F;
 class TH2F;
 class TProfile;
diff --git a/Validation/RecoVertex/interface/BeamSpotHistogramMaker.h b/Validation/RecoVertex/interface/BeamSpotHistogramMaker.h
index c7128de8dd32e..f653e78109122 100644
--- a/Validation/RecoVertex/interface/BeamSpotHistogramMaker.h
+++ b/Validation/RecoVertex/interface/BeamSpotHistogramMaker.h
@@ -5,14 +5,7 @@
 #include "FWCore/Framework/interface/ConsumesCollector.h"
 #include "FWCore/ParameterSet/interface/ParameterSet.h"
 #include "DPGAnalysis/SiStripTools/interface/RunHistogramManager.h"
-
-namespace edm {
-  class ParameterSet;
-}
-
-namespace reco {
-  class BeamSpot;
-}
+#include "DataFormats/BeamSpot/interface/BeamSpotFwd.h"
 
 class TH1F;
 class TProfile;