Update Rollups (there's a hint in the name) are an incremental set of updates, rolling up (told you) previous updates along with new updates for that release.
Currently for the 2012 R2 version we're on Update Rollup 4 (as of 02/12/14).
So after a new deployment of a System Center component, patch it to UR4 and you're ready to go, right?
You see, not all of the components always get updated with every UR, meaning that for some, UR3 might be the latest patch level even though UR4 is available.
I've pulled together the following table that shows the individual System Center 2012 R2 (I haven't pulled together the information for SP1 and if you're still on SP1, look to move to R2!)
|Component||UR1||UR2||UR3||UR4||Current Latest Level|
|Data Protection Manager||Yes||Yes||Yes||Yes||UR4|
|Virtual Machine Manager||Yes||Yes||Yes||Yes||UR4|
|Service Provider Foundation||Yes||Yes||No||Yes||UR4|
|Windows Azure Pack||WAP UR1||WAP UR2||WAP UR3||WAP UR4||WAP UR4|
N.B. ConfigMgr is slightly different in that they use "Cumulative Updates" and tend to be 1 version number behind the UR's (at least for a few months).
From this table we can clearly see that the majority of the components after a new install just need UR4 applying, but in the same vein we can see that SMA & Orchestrator still need you to dig out and apply UR3 or UR2 to them.
It also shows the it wasn't until UR2 that SCSM + SMA + Orchestrator got some loving, App Controller we now know is going the way of the Dodo and Service Reporting didn't need touching until UR4.
I think what I'm trying to explain here is don't just assume you need to grab the latest patch and you're done. Take some time to read the KB articles, see which components are updated, query your WSUS/ConfigMgr SUPs and plan appropriately.
Just for completeness, here are the latest release dates for versions of the Xplat Operating System Components:
SCOM Unix & Linux Monitoring - 28/10/2014
CM Unix & Linux Management - 30/10/2014
And to make it easier for you, here's all the KB articles for reference:
|System Center 2012 R2 UR1||http://support.microsoft.com/kb/2904734|
|System Center 2012 R2 UR2||http://support.microsoft.com/kb/2932881|
|System Center 2012 R2 UR3||http://support.microsoft.com/kb/2965090|
|System Center 2012 R2 UR4||http://support.microsoft.com/kb/2992012|
|ConfigMgr Clients for Additional OS'es||http://bit.ly/1w13F3s|
|SCOM MP for UNIX & Linux OS'es||http://bit.ly/1CCD27R|
** Updated - Orchestrator is only up to UR2, Orchestrator(SMA) is UR3) **