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Edit: Although the build number didn’t change, I notice that we can use ApplicationProperties.getVersion(), which returns the application version, which solves everything. Thanks!
I notice that https://jira.atlassian.com/browse/JRASERVER-77643 says the problem is with DataCenter platform version 6.5.3. This was bad enough that the Jira team pulled the Jira 9.15 and 9.15.1 releases.
Wouldn’t Confluence 8.9 be affected as well, since it was also built on DataCenter platform 6.5?