We don't have a clear rule for removing functions.

The function was removed as part of PR https://github.com/mantisbt/mantisbt/pull/1259 as it's no longer used in code and makes not that much sense in modern UI of 2.x.

@vboctor might comment, as he approved the PR.

My plugins are affected too
After 1 year of running fine in v2

We don't have a clear rule for removing functions.

We usually deprecate.
However, for all UI related, the experience is that they are removed without a flinch.

My intend was not to break anything, but just to cleanup code.

@cproensa @libregeek do you think we should reintroduce the function?

To prevent this situation in future, It would be good if you could invest some time to have a look at least at approved PRs.

do you think we should reintroduce the function?

Not at this point

FYI: I have solved it by copying the old function within my plugin namespace.

I'm not against deprecating functions, but it would be nice to mention such deprecations in release notes. Thus plugin developers can take a quick look at the release notes and fix it without doing a blind upgrade and breaking the production environments.

it would be nice to mention such deprecations in release notes

I've changed issue 0023754's title to make the function removal appear in the change log.

The function was removed as part of PR https://github.com/mantisbt/mantisbt/pull/1259

The "clean" way would have been to leave the function in, while having it trigger a USER_DEPRECATED error, and actually remove it in a later release. To keep in mind for future code cleanups :-)

The "clean" way would have been to leave the function in ...

Any function?
Isn't our official API just SOAP, REST and the events?

Does it mean that we also have to announce changes like incompatible function signature changes, removal/renaming of CSS classes, ...?