I apologize, what is MR5?
I guess its maintenance release 5 for ePO prior to upgrading to ePO 4.5
If you are planning to upgrade to ePO 4.5 patch4 then you can upgrade it from patch5 onwards.
The latest patch version is patch7 so if you are below patch5 then directly I will suggest you to upgrade to patch7 then ePO 4.5.
Please look at ePO 4.5 patch4 release notes. (https://kc.mcafee.com/corporate/index?page=content&id=KB71049&actp=search&viewlo cale=en_US&searchid=1304439356999)
Below is the snap
ePolicy Orchestrator 4.5 Patch 4 Server upgrade prerequisites
You must have one of the following installed prior to upgrading to ePolicy Orchestrator 4.5 Patch 4:
McAfee ePolicy Orchestrator 3.6.1 Patch 4 (build 255)
McAfee ePolicy Orchestrator 4.0 Patch 5 (build 1298)
McAfee ePolicy Orchestrator 4.0 Patch 6 (build 1333)
McAfee ePolicy Orchestrator 4.0 Patch 7 (build 1363)
The advantage is you can easily be able to be on a level where you can safely upgrade to ePO 45 version also take look at the ePO 4.0 P5 and ePO 4.0 P6 master release notes so you can see all the issues resolved by these 2 versions