Makes no sense to me. If it worked at an earlier version, it should work at the newer version. Suggest you go back to the person who said it and ask them what they meant.
MQ client (CD 9.1) connecting to QMGR with version 9.2.0.8 . There were few changes from MQ client as well ( MQ client version - CD version 9.1 to 9.2 ), Springboot 2.7 and started noticing ...