Migrating from earlier releases of IBM Semeru Certified Edition for z/OS

A summary of changes to the SDK and runtime environment that you must be aware of when you migrate from earlier releases of IBM® Semeru Certified Edition for z/OS® is listed here.

This release contains a few differences from Semeru Certified Edition for z/OS, version 17, which might require planning. For an overview, read the What's new section.

Important changes

If you are migrating from IBM Semeru Certified Edition for z/OS, Version 17, the following changes apply:
  • The zEDC (zEnterprise® Data Compression) Express adapter and the Integrated Accelerator for zEDC solution for z15® or later, which were supported in IBM Semeru Certified Edition for z/OS, Version 17, are not currently supported. As a result, the CPU consumption and performance of Java applications that make extensive use of data compression might be affected. Support is intended to be added in a later release.
  • The ZERTJSSE security provider, which was supported in the earlier Semeru versions such as Java 11 and 17, is not supported in the initial release of IBM Semeru Certified Edition for z/OS, Version 21.
  • Starting with JDK 18, UTF-8 is the default charset across platforms. The change to adopt UTF-8 might cause migration challenges for existing Java applications that are running on z/OS and that interact with non-UTF-8 files while you migrate to Semeru 21. For more information, see Migration from previous releases section in JEP 400 topic.
  • In the earlier Semeru versions such as Java 11 and 17, the property console.encoding was used to set the encoding of characters that are printed to the console (through System.out and System.err). The property helps to override the default console encoding.

    Since console.encoding is not supported in Java 21, use the properties stdout.encoding and stderr.encoding instead to change the default console encoding.

For information about JDK changes for each new release of Java, see the following documents.

These changes might affect the compatibility of applications with this release. For more information about these changes and how to determine whether your applications have compatibility issues, see Version compatibility.

Deprecations and removals

For a full list of JDK methods that are deprecated and removed, see Removed APIs, Tools, and Components.

Migrating from earlier releases

If you are migrating from a release before IBM Semeru Certified Edition for z/OS, Version 11, read the Migrating from earlier releases topic for Version 11.

If you are migrating from a release before IBM Semeru Certified Edition for z/OS, Version 17, read the Migrating from earlier releases topic for Version 17.