I can't move higher than 12 as we still have builds for the NRF51.
I see migration sections for 13 and 14 in infocenter. I can't find anything for 12 and I do know that there are a lot of changes (e.g. whitelisting) in 12. I just need a link to the SDK 12 Migration Guide and I can finish the changes needed to compile under the new SDK.