Potential problems

  1. After the EJB server has been migrated to CICS® TS for z/OS®, Version 3.1, some clients may have stale, cached, IORs that point to the old server. This is because some application servers cache the results of JNDI lookups locally to increase performance. You may find that these caches have to be purged before the new IORs are used.
  2. CICS TS for z/OS, Version 3.1 and CICS TS 2.3 support GIOP 1.2, whereas CICS TS 2.2 supports only GIOP 1.1. If a GIOP 1.2 message is received in a CICS TS 2.2 region it will be rejected. Under normal conditions this should never happen, because the maximum version of GIOP supported by CICS is stored in the IORs that CICS publishes. If a client knows that a given server only supports GIOP 1.1, it will never attempt to use anything more recent when communicating with that server. This means that CICS TS for z/OS, Version 3.1 can send GIOP messages to CICS TS 2.2.

    The problem will only occur if the client thinks it is talking to CICS TS for z/OS, Version 3.1 (or CICS TS 2.3) but its message is routed to a CICS TS 2.2 region. This will only happen if CICS TS 2.2 and CICS TS for z/OS, Version 3.1 regions are set up as sibling request processors (AORs) in the same logical server. (This is one reason why mixed-level logical servers are not recommended in CICS.) During a "rolling upgrade", the logical server does, of course, contain mixed-level request processors. However, if you follow the steps in Performing a "rolling upgrade", the problem (of a GIOP 1.2 message being received in a CICS TS 2.2 region) will not occur.

  3. CICS TS for z/OS, Version 3.1 and CICS TS 2.3 use a different format of IOR from CICS TS 2.2. If a GIOP 1.1 message intended for CICS TS for z/OS, Version 3.1 is routed to a CICS TS 2.2 region, the CICS TS 2.2 region will reject the request due to a unknown IOR format being in use. If all the regions in an EJB/CORBA server are at the same level of CICS and Java, this error cannot occur.

    During a "rolling upgrade", the logical server does, of course, contain mixed-level regions. However, if you follow the steps in Performing a "rolling upgrade", this problem will not occur.