DAVdroid 0.8, Android 5.1, Nexus 7 (2013) (deb)

java.lang.NullPointerException: Attempt to invoke virtual method 'boolean java.lang.String.equals(java.lang.Object)' on a null object reference
at at.bitfire.davdroid.resource.LocalAddressBook.populateRelation(LocalAddressBook.java:571)
at at.bitfire.davdroid.resource.LocalAddressBook.populate(LocalAddressBook.java:248)
at at.bitfire.davdroid.resource.LocalCollection.findById(LocalCollection.java:220)
at at.bitfire.davdroid.syncadapter.SyncManager.pushDirty(SyncManager.java:168)
at at.bitfire.davdroid.syncadapter.SyncManager.synchronize(SyncManager.java:50)
at at.bitfire.davdroid.syncadapter.DavSyncAdapter.onPerformSync(DavSyncAdapter.java:146)
at android.content.AbstractThreadedSyncAdapter$SyncThread.run(AbstractThreadedSyncAdapter.java:259)

(From Play Store)