My company is preparing to upgrade our SCCM site from 2012 R2 to 2012 R2 SP1 so we can have support for OSD with Windows 10.  Based on what I've read, it seems that the new SCCM client version that is deployed from 2012 R2 SP1 sites (5.00.8239.1203) cannot be used with or installed on Windows XP.  We still have a handful of XP systems in our environment that we have to be able to deploy to and manage, so having support for SCCM management of legacy operating systems is a must for us, at least for now.  In my test lab, after I upgraded my test site to 2012 R2 SP1, I was able to build a custom software package with the 2012 R2 (non-SP1) version of the SCCM client (5.00.7958.1000) to be installed during XP OSD task sequences only (all other clients/operating systems are successfully leveraging the newer client).  My XP test system is still able to communicate with my 2012 R2 SP1 site after imaging with the older client, and I have been able to deploy software to it and collect client information with no noticeable issues.

Has anyone done something similar with a 2012 R2 SP1 site (or other version) where you use several different client versions to both support newer operating systems and maintain compatibility with older operating systems?  I'm assuming that no issues will arise as long as we don't force an automatic client upgrade on XP systems, but I could be wrong as my test lab is not the most realistic and robust environment to prove this theory with.  So, any information or advice anyone can share is appreciated.  Thanks.

It's no problem if clients are using a version less than the site.

Thank you for the info!