diff --git a/CMakeLists.txt b/CMakeLists.txt
index 3c93a3252..ac59e3d86 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -29,6 +29,11 @@ option(
 	local sync timer"
 	ON )
 
+option(
+	RS_USE_CALENDAR
+	"Build RetroShare with GXS Calendar service support"
+	ON )
+
 option(
 	RS_BITDHT
 	"Use bitdht (BitTorrent DHT own implementation) to look for online peers"
@@ -674,7 +679,6 @@ target_compile_definitions(
 	RS_ENABLE_GXS
 	GXS_ENABLE_SYNC_MSGS
 	RS_USE_GXS_DISTANT_SYNC
-	RS_USE_CALENDAR
 	RS_GXS_TRANS
 	V07_NON_BACKWARD_COMPATIBLE_CHANGE_001
 	V07_NON_BACKWARD_COMPATIBLE_CHANGE_002
@@ -708,6 +712,11 @@ if(RS_GXS_SEND_ALL)
 		${PROJECT_NAME} PUBLIC RS_GXS_SEND_ALL )
 endif(RS_GXS_SEND_ALL)
 
+if(RS_USE_CALENDAR)
+	target_compile_definitions(
+		${PROJECT_NAME} PUBLIC RS_USE_CALENDAR )
+endif(RS_USE_CALENDAR)
+
 if(RS_BRODCAST_DISCOVERY)
 	## TODO: upstream option to disable tests building
 	set(BUILD_EXAMPLE OFF CACHE BOOL "Do not build udp-discovery-cpp examples")
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 1956a742b..0b40b0334 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -38,7 +38,6 @@ list(
 	retroshare/rsmail.h
 	retroshare/rsgxschannels.h
 	retroshare/rsgxscircles.h
-	retroshare/rsgxscalendar.h
 	retroshare/rsgxsiface.h
 	retroshare/rsgxsifacetypes.h
 	retroshare/rstypes.h
@@ -372,7 +371,6 @@ list(
 
 list(
 	APPEND RS_SOURCES
-	rsitems/rsgxscalendaritems.cc
 	rsitems/rsgxschannelitems.cc
 	rsitems/rsgxscircleitems.cc
 	rsitems/rsgxsitems.cc
@@ -395,7 +393,6 @@ list(
 	rsitems/rsbwctrlitems.h
 	rsitems/rsconfigitems.h
 	rsitems/rsfiletransferitems.h
-	rsitems/rsgxscalendaritems.h
 	rsitems/rsgxschannelitems.h
 	rsitems/rsgxscircleitems.h
 	rsitems/rsgxscommentitems.h
@@ -510,14 +507,12 @@ list(
 	services/p3msgservice.cc
 	services/p3idservice.cc
 	services/p3gxschannels.cc
-	services/p3gxsforums.cc
-	services/p3gxscalendar.cc )
+	services/p3gxsforums.cc )
 
 list(
 	APPEND RS_IMPLEMENTATION_HEADERS
 	services/p3banlist.h
 	services/p3bwctrl.h
-	services/p3gxscalendar.h
 	services/p3gxschannels.h
 	services/p3gxscircles.h
 	services/p3gxscommon.h
@@ -533,6 +528,22 @@ list(
 	services/p3serviceinfo.h
 	services/p3statusservice.h
 	services/rseventsservice.h )
+
+if(RS_USE_CALENDAR)
+	list(
+		APPEND RS_PUBLIC_HEADERS
+		retroshare/rsgxscalendar.h )
+
+	list(
+		APPEND RS_SOURCES
+		rsitems/rsgxscalendaritems.cc
+		services/p3gxscalendar.cc )
+
+	list(
+		APPEND RS_IMPLEMENTATION_HEADERS
+		rsitems/rsgxscalendaritems.h
+		services/p3gxscalendar.h )
+endif(RS_USE_CALENDAR)
 	
 #./services/p3wiki.cc
 #./services/p3wiki.h