diff --git a/common/rfb/CMsgHandler.h b/common/rfb/CMsgHandler.h
index 8e3c84e..5e333d2 100644
--- a/common/rfb/CMsgHandler.h
+++ b/common/rfb/CMsgHandler.h
@@ -57,8 +57,8 @@
     virtual void endOfContinuousUpdates();
     virtual void serverInit() = 0;
 
-    virtual void framebufferUpdateStart() = 0;
-    virtual void framebufferUpdateEnd() = 0;
+    virtual void framebufferUpdateStart();
+    virtual void framebufferUpdateEnd();
     virtual void dataRect(const Rect& r, int encoding) = 0;
 
     virtual void setColourMapEntries(int firstColour, int nColours,