CTG6431E The Gateway daemon has been started on an unsupported release of z/OS, V z/OS release
Explanation
The Gateway daemon has been started on a release of z/OS that is lower than the minimum supported release
System action
The CICS® Transaction Gateway fails to start
User response
Check the product documentation to verify the minimum supported release of z/OS for this release of CICS Transaction Gateway for z/OS. The product installation must be made available on a supported release of z/OS.