What is involved with upgrading from release Gen 8.5 to Gen 8.6?
Will z/OS Batch and Server programs need to be regenerated and installed?
Most applications built using Gen 8.5 (DLLs or Compatibility) do not need to be regenerated or reinstalled to work with Gen 8.6 runtimes.
It is expected that Gen 8.5 applications include changes introduced by Gen 8.0 PTFs RO40953 and RO53824, so no extra relinking is required to use Gen 8.6 runtimes.
Gen 8.5 removed the 32KB Common Format Buffer (CFB) limitation for CICS applications. To enable larger CFBs Gen uses dynamic allocation and management of certain data areas, namely views, CFB, GURB, GLOBAL-AREA and a number of internal buffers. The same memory management routines are used for data areas greater and smaller than 32KB. Details of this feature are documented in the Gen 8.5 Release Notes.
Gen 8.5 CICS applications migrating to Gen 8.6 that do not want to take advantage of the greater than 32KB CFB feature do not need to be regenerated or reinstalled. Greater than 32KB CFBs are not supported for IMS applications.
Changes made in Gen 8.5 to server-to-server applications (implemented in various PTFs) required regeneration and reinstallation when the PTFs were implemented so no further changes are necessary for these applications to use Gen 8.6 runtimes. Server-to-server changes introduced a new server runtime routine TIRPXMIT, which is included in TIRORUNC and TIRORUNI DLLs. TIRPXMIT is not used until the Server Manager is regenerated as part of applying the server-to-server PTFs (if cross-generation is used the co-required PTFs may not be z/OS PTFs). Once regeneration is done, deployment of these applications requires that the mentioned DLLs also be deployed.
If Gen 8.5 PTF RO86229 has already been applied, then the server should have been regenerated and installed at that time. If that was done then no further action is needed to use Gen 8.6. However, If the PTF was applied and the server was not regenerated and reinstalled, then that will need to be done.
Further details can be found on this Gen 8.6 documentation page: Gen™ 8.6 > Encyclopedia > Host Encyclopedia > Host Encyclopedia Construction > DLLs, Compatibility, and Application Migration in HE