Qsolved Question: Cisco used to have something called SafeHarbor that would allow one to look and see what was the recommended version for a particular Cisco model. Is there something like that now where the Cisco public can view the version numbers that the Cisco sources consider the safest as far as installs?
Qsolved Answer : SafeHarbor is a testing program that is not available for all Cisco Platforms.What I can suggest you is use the IOS Software Advisor: Click here for the link.
There you would be able to chose between different options to get a suggestion. You can do a search choosing type of hardware you have, the current feature set the device is running and you would get a suggestions.
However, if you have clear the reason of the upgrade (support hardware, new features, get latest code, etc) then it is always recommended to open a case with TAC and they would be able to look into you device and provide a better suggestions. Just keep in mind that TAC does not provide IOS recommendations, this is something that need more attention from your Cisco Account Team.