diff --git a/configure.ac b/configure.ac
index 7bca982f..ed7c1d6e 100644
--- a/configure.ac
+++ b/configure.ac
@@ -76,7 +76,7 @@ AC_PATH_PROG([GLIB_MKENUMS], [glib-mkenums])
 AX_COMPILER_FLAGS
 
 GLIB_MIN_VERSION=2.43.4
-GTK_MIN_VERSION=3.21.1
+GTK_MIN_VERSION=3.21.6
 ECAL_REQUIRED=3.13.90
 EDATASERVER_REQUIRED=3.17.1
 EDATASERVERUI_REQUIRED=3.17.1