You would need an add-on for this, since bulk user delete isn't supported in Jira yet:
The downside is that your version is quite old and no longer supported, so many of those add-ons may not work with your version.
You can give Bob Swift's Jira Command Line Interface a try, with the removeUser action. You can use runFromSql to do it in bulk. Please do keep in mind that it's only rated to work with Jira Server 7.1.0 - 7.5.3, so you may end up having to delete the users individually.
Let me know if you have any questions.
I’m a designer on the Jira team. For a long time, I’ve fielded questions from other designers about how they should be using Jira Software with their design team. I’ve also heard feedback from other ...
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