I have created an automation rule to edit the 'fix version' field with {{sprint.name}} in the current issue, when the sprint changes.
Unfortunately what it does is 'add' sprint name, rather than wipe the field and replace it with the new name, so that I end up with fix versions called 'sprint1.name'-sprint2.name'-'sprint3.name'-sprint4.name'
Is it possible to specify how the value should be changed? Maybe in more options? screengrab below

FYI, this was the original thread where I made that change.