SmartClient Power Edition 9.1p compatibility with Java 21 (WildFly environment)

[Ericsson]

Hello,

We are currently evaluating an upgrade of our platform runtime from Java 17 to Java 21 (LTS) and would like to confirm compatibility of our existing SmartClient version.

Our environment currently runs:

• SmartClient Power Edition: 9.1p (2014-03-23)
• Application Server: WildFly 37
• Current Java Runtime: Java 17
• Target Runtime: Java 21

Our application is a large enterprise platform with multiple microservices running on WildFly. The UI layer uses SmartClient, and we are reviewing whether any server-side SmartClient components might be impacted by the Java runtime upgrade.

Specifically we would like to confirm:

1. Whether SmartClient Power Edition 9.1p is known to run correctly on Java 21.
2. If there are any known runtime issues related to Java 21, such as:
   • reflection/module encapsulation restrictions
   • deprecated or removed JDK APIs
   • bytecode compatibility issues
3. Whether Isomorphic officially supports Java 21 with SmartClient, and if so, starting from which SmartClient version.
4. If our version is too old for Java 21, which minimum SmartClient version you recommend upgrading to.

For context, the application already runs successfully on WildFly 37 with Java 17, and we are performing a controlled upgrade to Java 21 across the platform.

Any guidance from the SmartClient team regarding compatibility or recommended upgrade paths would be greatly appreciated.

Thank you.

[Isomorphic]

Note to other readers: 9.1 is long past end-of-life. This customer has obtained special support arrangements.

This public post is a duplicate of a request that was sent via proper channels and was already being worked on - please do not do that, as you could have caused needless extra work.

It also looks like it might be garbled. We were previously asked about Java 25, not 21.

We ran our Showcase test suite on Java 25 and everything works except Hibernate/JPA and Spring, which was already the case (those libraries made breaking API changes without backcompat long after SmartClient 9.1 was released).

The latest SmartClient release (14.1) is compatible with those libraries on Java 25. If you're going to upgrade at all, you should go to 14.1, not any previous version.

[Ericsson]

Hi Isomorphic team,

We were originally interested in compatibility with both Java 21 and Java 25, but our current priority is Java 21.

Apologies for the duplicate request posted on the forum. I will continue the discussion through this email thread.

Thank you.