NX How can I find compatibility of SIMIT and NX MCD versions?

Update NX (e.g. to NX 2312) may need a compatible SIMIT version. What version of SIMIT can be used and are there any other considerations to be made for this type of upgrade?

Cannot find relevant documentation if there are compatibility issues with SIMIT and NX Mechatronics Concepts Designer.

NX does not certify the SIMIT version. It is SIMIT who owns the connection to NX (or other simulation clients). SIEMENS Factory Automation (FA) has a compatibility tool for that at SIOS (Siemens Industry Online Support):

http://www.siemens.com/kompatool  (see movie here: https://support.sw.siemens.com/knowledge-base/PL8792213) 

If you do not find the releases you are looking for (it might not be up-to-date for the newest NX versions), then the best option would be to ask via the FA support, Siemens Industry Online Support (SIOS) :

https://support.industry.siemens.com/cs/start?lc=en-WW

Notes