The numberToKeep param for snapshots doesn't work anymore. If you set the param to '2', only '1' backup is kept.
In the ReplicationHandler in line 377 snapShooter.validateCreateSnapshot(); creates an empty directory for the new snapshot. The deleteOldBackups() method in Snapshooter which will be executed before the backup is created, now sees the two directories an deletes the old one. But this is wrong because the empty directory for the new backup should not be considered.