In my current project we tried to process few interfaces as EOIO and we achieved by enabling it in Communication channel with queue name in version 7.3 single stack.
We had queue name as above it was working fine.
After upgrade of PI from 7.3 to 7.31 all the queues are getting struck in ECC in SMQ2 as below.
We have changed the queue name to
XBQA<queue name> high priority
XBQZ< queue name> low priority