This information is for those running 8.1 and using Hierarchary / Replication.
There have been implemented some changes in the Hierachy / Replication from 8.1 RU3. The changes can be seen in the Standalone Replication Rules where you are not able to select a server which is part of a hierachy. So if you use Standalone Replication Rule make sure you test this in a test environment before you upgrade.
For me the Standalone Replication rules did not work correctly anymore.
Support have confirmed the changes with RU3 and latera and the roadmap says to get rid of Standalone Replication for good with the next release at least for replicating items within hiearchy. It should be still be possible to “forward” using the rule for exampel to a standalone reporting server.