After upgrading Archive Manager to version 5.x you get the following retention error in the RPS.wlog
2015-11-06 15:30:14,155 [7] ERROR IncrementalUpgrader - {{d6962136-37c5-410b-9f8e-d20ee0571e6a}} Unable to upgrade Retention Engine; retrying
System.Data.SqlClient.SqlException (0x80131904): Timeout expired. The timeout period elapsed prior to completion of the operation or the server is not responding.
at System.Data.SqlClient.SqlConnection.OnError(SqlException exception, Boolean breakConnection)