diff --git a/configure.ac b/configure.ac
index 6b01da7d..3ebdc589 100644
--- a/configure.ac
+++ b/configure.ac
@@ -86,7 +86,7 @@ GTK_MIN_VERSION=3.15.4
 ECAL_REQUIRED=3.13.90
 EDATASERVER_REQUIRED=3.17.1
 EDATASERVERUI_REQUIRED=3.17.1
-LIBICAL_REQUIRED=0.43
+LIBICAL_REQUIRED=1.0
 GOA_MIN_VERSION=3.2.0
 
 PKG_CHECK_MODULES(CALENDAR,