QMF for TSO/CICS 12 has found no known issues running with z/OS 2.4. QMF for TSO/CICS adds support of 8 character TSO user ids (introduced in z/OS 2.3), with the fix for APAR PI99294. Users with 8 character TSO user ids using QMF for TSO/CICS should apply the fix for PI99294. No other problems or issues were found using z/OS 2.4 with QMF for TSO/CICS 12.
For the latest in QMF for TSO/CICS support of z/OS see the following technote:
http://www-01.ibm.com/support/docview.wss?uid=swg21570476