diff --git a/.ruby-version b/.ruby-version
index c1026d2..55bc983 100644
--- a/.ruby-version
+++ b/.ruby-version
@@ -1 +1 @@
-ruby-2.3.1
+ruby-2.4.1
diff --git a/.travis.yml b/.travis.yml
index b3bed0f..8a4c05a 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,5 +1,5 @@
 language: objective-c
-osx_image: xcode8.3
+osx_image: xcode9
 rvm:
   - "2.4.1"
 
diff --git a/Cartfile b/Cartfile
index 313c24d..4cb3fb3 100644
--- a/Cartfile
+++ b/Cartfile
@@ -1 +1 @@
-github "ReactiveX/RxSwift" ~> 3.4
+github "ReactiveX/RxSwift" ~> 4.0
diff --git a/Cartfile.resolved b/Cartfile.resolved
index c3b4814..d070f13 100644
--- a/Cartfile.resolved
+++ b/Cartfile.resolved
@@ -1 +1 @@
-github "ReactiveX/RxSwift" "3.5.0"
+github "ReactiveX/RxSwift" "4.0.0"
diff --git a/Carthage/Checkouts/RxSwift b/Carthage/Checkouts/RxSwift
index 520b1db..12cccb1 160000
--- a/Carthage/Checkouts/RxSwift
+++ b/Carthage/Checkouts/RxSwift
@@ -1 +1 @@
-Subproject commit 520b1db2237f55763c7b6211dc9d8255967eee69
+Subproject commit 12cccb171ad9038251af6883807f0290c1d75a5b
diff --git a/Demo/.swift-version b/Demo/.swift-version
index 9f55b2c..5186d07 100644
--- a/Demo/.swift-version
+++ b/Demo/.swift-version
@@ -1 +1 @@
-3.0
+4.0
diff --git a/Demo/Podfile b/Demo/Podfile
index ec0814f..649a0fc 100644
--- a/Demo/Podfile
+++ b/Demo/Podfile
@@ -14,11 +14,11 @@ def library
 end
 
 target 'Demo' do
-  platform :ios, '8.0'
+  platform :ios, '9.0'
   library
 
   target 'RxViewModelTests-iOS' do
-      platform :ios, '8.0'
+      platform :ios, '9.0'
       inherit! :search_paths
 
       test_pods
@@ -37,4 +37,4 @@ target 'RxViewModelTests-macOS' do
     library
 
     test_pods
-end
\ No newline at end of file
+end
diff --git a/Demo/Podfile.lock b/Demo/Podfile.lock
index 8a08796..03e0877 100644
--- a/Demo/Podfile.lock
+++ b/Demo/Podfile.lock
@@ -1,9 +1,9 @@
 PODS:
-  - Nimble (7.0.1)
-  - Quick (1.1.0)
-  - RxSwift (3.5.0)
-  - RxViewModel (4.0.0):
-    - RxSwift (~> 3.5.0)
+  - Nimble (7.0.2)
+  - Quick (1.2.0)
+  - RxSwift (4.0.0)
+  - RxViewModel (5.1.0):
+    - RxSwift (~> 4.0)
 
 DEPENDENCIES:
   - Nimble
@@ -15,11 +15,11 @@ EXTERNAL SOURCES:
     :path: "../"
 
 SPEC CHECKSUMS:
-  Nimble: 657d000e11df8aebe27cdaf9d244de7f30ed87f7
-  Quick: dafc587e21eed9f4cab3249b9f9015b0b7a7f71d
-  RxSwift: 18ee9d78b45edb3b0b7e79916b47a116e6dbc842
-  RxViewModel: f9dbd276b3bdc9858cf8ef7cf032fe199ddb27f6
+  Nimble: bfe1f814edabba69ff145cb1283e04ed636a67f2
+  Quick: 58d203b1c5e27fff7229c4c1ae445ad7069a7a08
+  RxSwift: fd680d75283beb5e2559486f3c0ff852f0d35334
+  RxViewModel: 4fda1b24076c00dee8993015e12bce17091b8fb7
 
-PODFILE CHECKSUM: 5b740ff0f8e82b1a56bee6decd0acad5bd6013b9
+PODFILE CHECKSUM: f3dc2ef276e60482f87b2abfca65a634f6640961
 
 COCOAPODS: 1.2.1
diff --git a/Rakefile b/Rakefile
index c218bb3..9e784a3 100644
--- a/Rakefile
+++ b/Rakefile
@@ -26,7 +26,7 @@ def sdks
   return {
     ios: 'iphonesimulator',
     macos: 'macosx',
-    tvos: 'appletvsimulator10.2'
+    tvos: 'appletvsimulator11.0'
   }
 end
 
diff --git a/RxViewModel.podspec b/RxViewModel.podspec
index f83554f..752c1f3 100644
--- a/RxViewModel.podspec
+++ b/RxViewModel.podspec
@@ -1,7 +1,7 @@
 
 Pod::Spec.new do |s|
   s.name             = "RxViewModel"
-  s.version          = "5.0.1"
+  s.version          = "5.1.0"
   s.summary          = "`RxViewModel` is the marriage between `MVVM` and `Rx` extensions. A blatant «imitation» of `ReactiveViewModel` using `RxCocoa`."
   s.description      = <<-DESC
 `RxViewModel` is the marriage between `MVVM` and `Rx` extensions
@@ -25,6 +25,6 @@ Long story short: a blatant «imitation» of `ReactiveViewModel `using `RxCocoa`
   s.requires_arc = true
 
   s.source_files = 'Source/*.swift', 'Source/Categories/*.swift'
-  s.dependency 'RxSwift', '~> 3.5'
+  s.dependency 'RxSwift', '~> 4.0'
   s.frameworks = 'Foundation'
 end
diff --git a/Source/RxViewModel.swift b/Source/RxViewModel.swift
index 252b790..6cc0929 100644
--- a/Source/RxViewModel.swift
+++ b/Source/RxViewModel.swift
@@ -28,7 +28,7 @@ open class RxViewModel: NSObject {
   private dynamic var _active: Bool = false
   
   /// Public «active» variable
-  public dynamic var active: Bool {
+  @objc public dynamic var active: Bool {
     get { return _active }
     set {
       // Skip KVO notifications when the property hasn't actually changed. This is