I upgraded my sdk from 2.6.1 to 3.1.1 and after resolving a few issues everything was working just as it was before the upgrade except for MCUmgr. When I run the MCUmgr client on my PC after the upgrade, the server on the nRF52850 does not reply to any requests. It's difficult to know exactly what is happening. I don't get any error messages. No replies. Eventually the client just times out. This works perfectly under sdk 2.6.1.
Is that anything additional I have to do? A special Kconfig? Is there a release note that discusses this issue?