This is my issue as well. We have a mix of MR33s + some older MR24s/MR16s for a client.
I have tried the 25.5/6 on our office network (two MR52s) and found that MacBook Pros and some iPads will simply not connect to the wifi. We reverted back to the latest production version and no problems.
Not sure I really want to take that risk for production kit not at our office.