Not able to select any version to get Bitbucket upgrade instructions
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Note that this knowledge base article was created for the Data Center version of the product. Data Center knowledge base articles for non-Data Center-specific features may also work for Server versions of the product, however they have not been tested. Support for Server* products ended on February 15th 2024. If you are running a Server product, you can visit the Atlassian Server end of support announcement to review your migration options.
*Except Fisheye and Crucible
Summary
In preparation for Bitbucket Upgrade, it's not possible to select any version to get the upgrade instructions:
Environment
Bitbucket 7.16.0.
Diagnosis
There are no errors in the logs. When accessing the http://bb_url/plugins/servlet/troubleshooting/pre-upgrade/ page, the page above is prompted in UI.
Cause
The issue is happening due to a bug in the version of ATST (plugin) that's bundled with Bitbucket 7.16.0. Currently, there's no way to upgrade ATST by itself in the application. Bitbucket Server 7.18.0 and newer bundle a version of ATST that has the bug fixed.
Solution
Upgrade Bitbucket to 7.18+ version. The instructions to upgrade are listed in Bitbucket Server upgrade guide.