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

A summary of changes to the SDK and runtime environment that you need to 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 11, 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 11, the following changes apply:

z/OS 2.4, which was supported in IBM Semeru Certified Edition for z/OS, Version 11, is not supported in this release.
The zEDC (zEnterprise® Data Compression) Express adapter and the Integrated Accelerator for zEDC solution for z15® or later, which was supported in IBM Semeru Certified Edition for z/OS, Version 11, but was not available in the first release of Version 17, is now supported. For more information, see zEnterprise Data Compression.
Starting from Java 11, fonts are no longer bundled with the SDK. Semeru now relies on system-installed WorldType fonts. The latest version of WorldType fonts is found as UNIX files (Hierarchical File System (HFS) or z/OS® File System (zFS) files) in this location:
```
/usr/lpp/fonts/worldtype
```
For more information on font support, see Semeru fonts support on z/OS.
In contrast to IBM Java 8, Semeru SDKs contain an intentional correction of what processing is dispatched to IBM z Integrated Information Processor (zIIP) that can cause an increment in general central processor (CP) usage for some specific workloads. The change is working as designed and corrects a situation in Java 8 where some processing was dispatched to zIIP when it was not zIIP eligible.
In Java 11 and earlier versions, when the JVM loads an application native library (DLL), it searches for the library in the path that is specified in both the system property java.library.path and the LIBPATH environment variable. From Java 17 onwards, the search is based only off the system property java.library.path, which is set when the JVM starts. Changing the java.library.path property after JVM starts does not affect the search path. The default java.library.path is derived from the LIBPATH environment variable. If the java.library.path is set on the command line, this value is used exclusively for the search and the path that is mentioned in LIBPATH is not used for searching the libraries.

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.