diff --git a/ChangeLog b/ChangeLog
index 862cd95fb..0d67ba961 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,15 @@
 2012-03-16  Wolfgang Sourdeau  <wsourdeau@inverse.ca>
 
+	* OpenChange/MAPIStoreGCSFolder.m
+	(-updateVersionsForMessageWithKey:withChangeKey:): new method,
+	common to all GCS messages, that updates the folder cache and
+	insert the PidTagChangeKey provided by the client during the save
+	operations.
+
+	* OpenChange/MAPIStoreGCSMessage.m (-updateVersions): new proxy
+	method for -[MAPIStoreGCSFolder
+	updateVersionsForMessageWithKey:withChangeKey:].
+
 	* OpenChange/MAPIStoreGCSBaseContext.m
 	(+createRootSecondaryFolderWithFID:andName:forUser:): setup the
 	userContext in the MAPIApp object.
diff --git a/OpenChange/MAPIStoreCalendarMessage.m b/OpenChange/MAPIStoreCalendarMessage.m
index bd299eb35..3c657b47d 100644
--- a/OpenChange/MAPIStoreCalendarMessage.m
+++ b/OpenChange/MAPIStoreCalendarMessage.m
@@ -1064,12 +1064,7 @@
   if (newParticipationStatus)
     [sogoObject changeParticipationStatus: newParticipationStatus
                              withDelegate: nil];
-
-  [(MAPIStoreCalendarFolder *) container synchroniseCache];
-  value = [properties objectForKey: MAPIPropertyKey (PR_CHANGE_KEY)];
-  if (value)
-    [(MAPIStoreCalendarFolder *) container
-    setChangeKey: value forMessageWithKey: [self nameInContainer]];
+  [self updateVersions];
 }
 
 - (id) lookupAttachment: (NSString *) childKey
diff --git a/OpenChange/MAPIStoreContactsMessage.m b/OpenChange/MAPIStoreContactsMessage.m
index d1bdebadc..c8af5c05b 100644
--- a/OpenChange/MAPIStoreContactsMessage.m
+++ b/OpenChange/MAPIStoreContactsMessage.m
@@ -1157,11 +1157,8 @@ fromProperties: (NSDictionary *) attachmentProps
   // we save the new/modified card
   //
   [sogoObject saveContentString: [newCard versitString]];
-  [(MAPIStoreContactsFolder *) container synchroniseCache];
-  value = [properties objectForKey: MAPIPropertyKey (PR_CHANGE_KEY)];
-  if (value)
-    [(MAPIStoreContactsFolder *) container
-    setChangeKey: value forMessageWithKey: [self nameInContainer]];
+
+  [self updateVersions];
 }
 
 @end
diff --git a/OpenChange/MAPIStoreGCSFolder.h b/OpenChange/MAPIStoreGCSFolder.h
index d87c9c63c..0d0c1e6df 100644
--- a/OpenChange/MAPIStoreGCSFolder.h
+++ b/OpenChange/MAPIStoreGCSFolder.h
@@ -41,6 +41,8 @@
 
 /* synchronisation */
 - (BOOL) synchroniseCache;
+- (void) updateVersionsForMessageWithKey: (NSString *) messageKey
+                           withChangeKey: (NSData *) newChangeKey;
 - (NSNumber *) lastModifiedFromMessageChangeNumber: (NSNumber *) changeNum;
 - (NSNumber *) changeNumberForMessageWithKey: (NSString *) messageKey;
 
diff --git a/OpenChange/MAPIStoreGCSFolder.m b/OpenChange/MAPIStoreGCSFolder.m
index 74c784c93..57cb9b123 100644
--- a/OpenChange/MAPIStoreGCSFolder.m
+++ b/OpenChange/MAPIStoreGCSFolder.m
@@ -252,7 +252,7 @@ static Class NSNumberK;
     ...
   };
   VersionMapping = {
-    Version = MessageKey;
+    Version = last-modified;
     ...
   }
 }
@@ -458,6 +458,15 @@ static Class NSNumberK;
 
   return rc;
 }
+
+- (void) updateVersionsForMessageWithKey: (NSString *) messageKey
+                           withChangeKey: (NSData *) newChangeKey
+{
+  [self synchroniseCache];
+
+  if (newChangeKey)
+    [self setChangeKey: newChangeKey forMessageWithKey: messageKey];
+}
  
 - (NSNumber *) lastModifiedFromMessageChangeNumber: (NSNumber *) changeNum
 {
diff --git a/OpenChange/MAPIStoreGCSMessage.h b/OpenChange/MAPIStoreGCSMessage.h
index 883923e5f..5ada9290b 100644
--- a/OpenChange/MAPIStoreGCSMessage.h
+++ b/OpenChange/MAPIStoreGCSMessage.h
@@ -29,6 +29,9 @@
 {
 }
 
+/* subclass helpers */
+- (void) updateVersions;
+
 @end
 
 #endif /* MAPISTOREGCSMESSAGE_H */
diff --git a/OpenChange/MAPIStoreGCSMessage.m b/OpenChange/MAPIStoreGCSMessage.m
index 4d7ea0c07..c62f87990 100644
--- a/OpenChange/MAPIStoreGCSMessage.m
+++ b/OpenChange/MAPIStoreGCSMessage.m
@@ -21,6 +21,7 @@
  */
 
 #import <Foundation/NSCalendarDate.h>
+#import <Foundation/NSDictionary.h>
 #import <Foundation/NSValue.h>
 #import <NGObjWeb/SoSecurityManager.h>
 #import <NGExtensions/NSObject+Logs.h>
@@ -204,4 +205,15 @@
   return version;
 }
 
+- (void) updateVersions
+{
+  NSData *newChangeKey;
+
+  newChangeKey = [properties objectForKey: MAPIPropertyKey (PR_CHANGE_KEY)];
+
+  [(MAPIStoreGCSFolder *) container
+    updateVersionsForMessageWithKey: [self nameInContainer]
+                      withChangeKey: newChangeKey];
+}
+
 @end
diff --git a/OpenChange/MAPIStoreTasksMessage.m b/OpenChange/MAPIStoreTasksMessage.m
index 28d690b74..5e123fab7 100644
--- a/OpenChange/MAPIStoreTasksMessage.m
+++ b/OpenChange/MAPIStoreTasksMessage.m
@@ -462,11 +462,8 @@
   [vToDo setTimeStampAsDate: now];
 
   [sogoObject saveContentString: [vCalendar versitString]];
-  [(MAPIStoreTasksFolder *) container synchroniseCache];
-  value = [properties objectForKey: MAPIPropertyKey (PR_CHANGE_KEY)];
-  if (value)
-    [(MAPIStoreTasksFolder *) container
-    setChangeKey: value forMessageWithKey: [self nameInContainer]];
+
+  [self updateVersions];
 }
 
 @end