Guava 11 is bundled with the 1.86.2 version

[yzakharuk-iqmessenger]

The latest (1.86.2) version of the plugin bundle contains Guava 11 jar file. This may cause problems as the latest versions of Jenkins core contains a much newer version of Guava (In my case, this cause VerifyError: class com.google.common.collect.EmptyImmutableSortedSet overrides final method com.google.common.collect.ImmutableCollection.toArray()[Ljava/lang/Object; errors.).

As far as I understand, the plugin should not contain any version of the Guava library but use the provided version.

[tomasbjerre]

Thanks for reporting, should be fixed now.