diff --git a/.github/workflows/ccpp.yml b/.github/workflows/ccpp.yml
index dcc73133c..44695ef2a 100644
--- a/.github/workflows/ccpp.yml
+++ b/.github/workflows/ccpp.yml
@@ -37,7 +37,7 @@ jobs:
               export CC_LD=lld
             fi
             export CC=${{ matrix.compiler }}
-            ./autogen.sh && ./configure --enable-mandoc --enable-golang && make -j
+            ./autogen.sh && ./configure --enable-mandoc --enable-golang --enable-mpack && make -j
           fi
           if [ "${{ matrix.build-system }}" = "meson" ]; then
             if [ "${{ matrix.compiler }}" = "gcc" ]; then
@@ -46,7 +46,7 @@ jobs:
               export CC_LD=lld
             fi
             export CC=${{ matrix.compiler }}
-            meson setup builddir -Dhtmldoc=true -Dmandoc=true && ninja -C builddir
+            meson setup builddir -Dhtmldoc=true -Dmandoc=true -Dmcomms=true && ninja -C builddir
           fi
 
   notification:
diff --git a/configure.ac b/configure.ac
index d07760925..c2fc950dc 100644
--- a/configure.ac
+++ b/configure.ac
@@ -94,6 +94,21 @@ fi
 AM_CONDITIONAL([FVWM_BUILD_GOLANG], [test x"$with_golang" = xyes])
 AC_SUBST(GO)
 
+# mpack
+problem_mpack=""
+AH_TEMPLATE([HAVE_MPACK], [Define MPACK])
+AC_ARG_ENABLE(mpack,
+	      AS_HELP_STRING([--enable-mpack],[enable mpack module comms]),
+	      [ if test x"$enableval" = "xyes"; then
+		  with_mpack="yes"
+		else
+		  with_mpack="no"
+		  problem_mpack=": Explicitly disabled"
+		fi ],
+	      [ with_mpack="no" ]
+)
+
+
 #!!!
 PERL=""
 REQUIRED_PERL_VERSION=5.004
@@ -745,6 +760,13 @@ fi
 AC_SUBST(png_LIBS)
 AC_SUBST(png_CFLAGS)
 
+yes_to_mpack="no"
+if test "$with_mpack" = "yes"; then
+  PKG_CHECK_MODULES([mpack], [mpack], [yes_to_mpack="yes"], [])
+fi
+
+AM_CONDITIONAL([HAVE_MPACK], [test x"$yes_to_mpack" = xyes])
+
 # ********* rsvg
 rsvg_min_version=2.13.92
 AH_TEMPLATE([HAVE_RSVG], [Define if librsvg library is used.])
@@ -1508,6 +1530,7 @@ Fvwm3 Configuration:
   With XPM image support?             $with_xpm$problem_xpm
   With Xrender image support?         $with_xrender$problem_xrender
   With Golang support?                $with_golang$problem_golang
+  With mpack support?		      $with_mpack$problem_mpack
   Build man pages?                    $with_mandoc$problem_mandoc
   Build html man pages?               $with_htmldoc$problem_htmldoc
 
diff --git a/fvwm/module_list.c b/fvwm/module_list.c
index 6b0d38092..2c3dc9efd 100644
--- a/fvwm/module_list.c
+++ b/fvwm/module_list.c
@@ -1120,6 +1120,7 @@ void CMD_ModuleSynchronous(F_CMD_ARGS)
 		token = PeekToken(next, &next);
 		if (token)
 		{
+			free(expect);
 			expect = fxstrdup(token);
 		}
 		action = next;
diff --git a/libs/Makefile.am b/libs/Makefile.am
index 848fa3fdd..eb8fd64e1 100644
--- a/libs/Makefile.am
+++ b/libs/Makefile.am
@@ -38,6 +38,10 @@ else
 libfvwm3_a_SOURCES += strlcpy.h strlcat.h strlcpy.c strlcat.c
 endif
 
+if HAVE_MPACK
+libfvwm3_a_SOURCES += mcomms.c mcomms.h
+endif
+
 libfvwm3_a_LIBADD = @LIBOBJS@
 
 AM_CPPFLAGS = -I$(top_srcdir) $(xpm_CFLAGS) $(Xft_CFLAGS) $(X_CFLAGS) \
diff --git a/libs/mcomms.c b/libs/mcomms.c
new file mode 100644
index 000000000..0f4b0e95e
--- /dev/null
+++ b/libs/mcomms.c
@@ -0,0 +1,63 @@
+/* This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see: <http://www.gnu.org/licenses/>
+ */
+
+#include <stdio.h>
+#include <stdint.h>
+
+#include "config.h"
+#include "log.h"
+#include "safemalloc.h"
+#include "mcomms.h"
+
+uint64_t m_find_bit(const char *);
+
+static const struct {
+	uint64_t	 bits;
+	const char	*name;
+} all_mcomm_types[] = {
+	{ MCOMMS_NEW_WINDOW, "new-window" },
+	{ 0, NULL },
+};
+
+uint64_t
+m_find_bit(const char *name)
+{
+	int i = 0;
+
+	for (i = 0; all_mcomm_types[i].name != NULL; i++) {
+		if (strcmp(all_mcomm_types[i].name, name) == 0) {
+			return all_mcomm_types[i].bits;
+		}
+	}
+	fprintf(stderr, "%s: Invalid module interest: %s\n", __func__, name);
+	return 0;
+}
+
+uint64_t
+m_register_interest(int *fd, const char *me)
+{
+	char		*me1;
+	const char	*component;
+	uint64_t	 m_bits = 0;
+
+	if (me == NULL)
+		return 0;
+	me1 = fxstrdup(me);
+
+	while ((component = strsep(&me1, " ")) != NULL)
+		m_bits |= m_find_bit(component);
+
+	free(me1);
+	return m_bits;
+}
diff --git a/libs/mcomms.h b/libs/mcomms.h
new file mode 100644
index 000000000..65466f4a8
--- /dev/null
+++ b/libs/mcomms.h
@@ -0,0 +1,44 @@
+#ifndef FVWMLIB_MCOMMS_H
+#define FVWMLIB_MCOMMS_H
+
+#include <stdbool.h>
+
+#define MCOMMS_NEW_WINDOW	0x0000000000000001ULL
+#define MCOMMS_ALL		0xffffffffffffffffULL
+
+struct m_add_window {
+	char	*window;
+	int	 title_height;
+	int	 border_width;
+
+	struct {
+		int	window;
+		int	x;
+		int	y;
+		int	width;
+		int	height;
+	} frame;
+
+	struct {
+		int	base_width;
+		int	base_height;
+		int	inc_width;
+		int	inc_height;
+		int	orig_inc_width;
+		int	orig_inc_height;
+		int	min_width;
+		int	min_height;
+		int	max_width;
+		int	max_height;
+	} hints;
+
+	struct {
+		int	layer;
+		int	desktop;
+		int	window_type;
+	} ewmh;
+};
+
+uint64_t	m_register_interest(int *, const char *);
+
+#endif
diff --git a/libs/meson.build b/libs/meson.build
index 13d8a4dde..f5d2b7f78 100644
--- a/libs/meson.build
+++ b/libs/meson.build
@@ -63,6 +63,12 @@ string_sources = files(
     'strlcpy.c',
 )
 
+if (mpack.found())
+    libfvwm3_sources += files(
+      'mcomms.c'
+    )
+endif
+
 # We don't build the string sources on macOS
 # We probably could check for target_system, but nobody is cross-compiling _to_ macOS
 if not (host_machine.system() == 'darwin')
diff --git a/meson.build b/meson.build
index 3c91ec906..a134e91a6 100644
--- a/meson.build
+++ b/meson.build
@@ -197,6 +197,13 @@ foreach rd : all_req_deps
     all_found_deps += this_dep
 endforeach
 
+mpack = dependency('mpack', required: get_option('mcomms'))
+if mpack.found()
+    all_found_deps += mpack
+    summary_depvals += {'mpack': mpack}
+    conf.set10('HAVE_MPACK', true)
+endif
+
 xext = dependency('xext', required: true)
 all_found_deps += xext
 summary_depvals += {'xext': xext}
diff --git a/meson.options b/meson.options
index 17823077b..717a4c09e 100644
--- a/meson.options
+++ b/meson.options
@@ -57,6 +57,12 @@ option(
     value: false,
     description: 'Enable generation of man pages',
 )
+option(
+    'mcomms',
+    type: 'boolean',
+    value: false,
+    description: 'Enable new module comms',
+)
 option('nls', type: 'feature', value: 'auto', description: 'Enable NLS')
 option('png', type: 'feature', value: 'auto', description: 'Enable png support')
 option(
diff --git a/modules/FvwmIdent/FvwmIdent.c b/modules/FvwmIdent/FvwmIdent.c
index f60ef65da..d351e96af 100644
--- a/modules/FvwmIdent/FvwmIdent.c
+++ b/modules/FvwmIdent/FvwmIdent.c
@@ -55,6 +55,10 @@
 #include "libs/XError.h"
 #include "libs/log.h"
 
+#ifdef HAVE_MPACK
+#include "libs/mcomms.h"
+#endif
+
 #include "FvwmIdent.h"
 
 static RETSIGTYPE TerminateHandler(int);
@@ -213,7 +217,10 @@ int main(int argc, char **argv)
 
 	InitGetConfigLine(fd, mname);
 	GetConfigLine(fd,&tline);
-
+#ifdef HAVE_MPACK
+	fprintf(stderr, "GOT: %lu\n",
+		m_register_interest(fd, "new-window this that the-other"));
+#endif
 	while (tline != (char *)0)
 	{
 		if (strlen(tline) <= 1)