Is anyone aware of either known issues or supported configurations between the binaries of AX 2012 R2 and R2 with CU6 installed. For example, is it safe for a CU6 client to connect to an R2 AOS, or even an R2 client to connect to a CU6 AOS.
I had read somewhere in the past that as part of hotfixes and cumulative updates (a collection of many hotfixes) that Microsoft would not create binary and AOT dependencies, but I can no longer locate this blog article, and additionally I have seen such dependencies in recent years.
You should always run the same version of the client as the AOS. If they are on different versions, you run the risk of RPC exceptions or worse if the call between the server and client has changed in any way - which will happen with hotfixes. This can lead to your AOS crashing or dropped client connections, which of course we all want to avoid.
As i understand, the client and server components should always stay on the same version. Usually, you will get error message that tell you the mismatch of version in your environment.
It seems smart to keep them the same whenever possible, and I have seen combinations in the past where they did not work (whether they complained or not at the time I can not remember).
However, today I am able to connect to a 188.8.131.52 AOS from the 6.2.1000.1437 client, and also to a 6.2.1000.1437 AOS from a 184.108.40.206 client, without any warning or error. I haven't taken it any further to see if it breaks under stress or across all features and functions, but merely connecting does give one pause for thought.
Recently, i built a new environment with R2 + CU6 contoso db and with R2 + CU1 for both Client and AOS (accidentally forgot to change the slipstreaming with CU6 package).
The result turn out to be client was installed successfully. However, AOS did installed but failed to start because of the db version is greater than AOS.
I guess is kind of a rare cases where you might want to run on a different version of binary on client and AOS. I remember when AX 2009 generation, where it does support by running multiple version of client and AOS in the same machine.