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Upgrading DS (All versions) fails with UnsupportedClassVersion error

Last updated Jun 15, 2021

The purpose of this article is to provide assistance if the DS server fails to upgrade to a later version with "Exception in thread "main" java.lang.UnsupportedClassVersionError".


An error similar to the following is shown when the upgrade fails:

Exception in thread "main" java.lang.UnsupportedClassVersionError: org/opends/server/tools/upgrade/UpgradeCli : Unsupported major.minor version 52.0    at java.lang.ClassLoader.defineClass1(Native Method)      at java.lang.ClassLoader.defineClass(      at      at      at$100(      at$      at$      at Method)      at      at java.lang.ClassLoader.loadClass(      at sun.misc.Launcher$AppClassLoader.loadClass(      at java.lang.ClassLoader.loadClass(      at sun.launcher.LauncherHelper.checkAndLoadMain(

The same error is shown in the Upgrade.log file.

Recent Changes



The version of DS you are upgrading to requires a different version of Java® than the one running on your server. The Java versions required are as follows:

  • DS 7 - Java 11
  • DS 6.5.x - Java 8 or 11
  • DS 6 - Java 8 or 9

See the release notes applicable to your version for further information, for example: DS 7.1 Java.


This issue can be resolved by installing the required version of Java and then enabling the server to use the newer version as detailed in How do I change DS (All versions) to use a different JDK version?

Once Java is successfully updated, you can then upgrade the DS server.

See Also

How do I ensure DS (All versions) uses the Java settings from file when starting?

Upgrading DS

Upgrade Guide

Related Training


Related Issue Tracker IDs


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