If you are working on an AX2012 R3 implementation you might want to have a look at CU12 that was just released. You can read the What’s new document here.
There are some nice updates to technology support like SQL2016 and some functional updates along with fixes. For example being able to run a depreciation run across companies, which is nice if you have many legal entities that you use fixed assets for. This feature was in the fall release of D365 as well.
The KB was listed as KB3199741 which you can find on partnersource here. As well you can find it under the updates tile on Lifecycle Services.