diff --git a/CMakeLists.txt b/CMakeLists.txt
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -70,7 +70,7 @@
 set(AKONADI_VERSION "5.11.40")
 
 set(KCONTACTS_LIB_VERSION "5.11.40")
-set(KCALENDARCORE_LIB_VERSION "5.11.42")
+set(KCALENDARCORE_LIB_VERSION "5.11.43")
 set(IDENTITYMANAGEMENT_LIB_VERSION "5.11.40")
 set(KMAILTRANSPORT_LIB_VERSION "5.11.40")
 set(CALENDARUTILS_LIB_VERSION "5.11.40")
diff --git a/resources/kolab/pimkolab/autotests/testutils.h b/resources/kolab/pimkolab/autotests/testutils.h
--- a/resources/kolab/pimkolab/autotests/testutils.h
+++ b/resources/kolab/pimkolab/autotests/testutils.h
@@ -134,9 +134,11 @@
 {
     //The UID is not persistent (it's just the internal pointer), therefore we clear it
     //TODO make sure that the UID does really not need to be persistent
-    foreach (KCalCore::Attendee::Ptr attendee, incidence->attendees()) {
+    auto attendees = incidence->attendees();
+    for (auto &attendee : attendees) {
         attendee->setUid(QString());
     }
+    incidence->setAttendees(attendees);
 
     //FIXME even if hasDueDate can differ, it shouldn't because it breaks equality. Check why they differ in the first place.
     if (incidence->type() == KCalCore::IncidenceBase::TypeTodo) {