diff --git a/configure.ac b/configure.ac
index 1efe99d8..cb96c7ab 100644
--- a/configure.ac
+++ b/configure.ac
@@ -112,7 +112,7 @@ dnl ***********************************************************************
 dnl Check for required packages
 dnl ***********************************************************************
 m4_define([glib_required_version], [2.44.0])
-m4_define([gtk_required_version], [3.21.4])
+m4_define([gtk_required_version], [3.21.5])
 m4_define([systemd_required_version], [222])
 
 PKG_CHECK_MODULES(GIO,