I'm not sure if I've made the purpose of the modification clear: It conditionally allows to suppress the reopening because so far it always reopens with respect to the global MantisBT configuration options

Forum or MantisBT ticket is fine.

EmailReporting tries to emulate MantisBT in user experience. Since MantisBT does not allow to disable this except with permissions, neither does EmailReporting.
We can evaluate the code if you provide a pull request on the EmailReporting github project page.
I understand you have little experience with github so if figuring out github is too much you can provide a download link to the changed files (please only the changed files). If the zipped package is small enough you might also be able to attach it to this ticket.

I have opened a pull request: https://github.com/mantisbt-plugins/EmailReporting/pull/38

I tested with MantisBT 2.27.0, 2.26.4, and 2.25.2. Seems my VSC messed up the original tab size, unfortunately I didn't find out how to fix this.

This solution works for me, it may be too naive with respect to your quality requirements.

If this is merged I can also edit the plugin's wiki page to document the configuration option. I hope I haven't missed out sth. important.

One more thought on this and its relevance. I have searched quite a while to suppress reopening and found a considerable number of discussions where this feature is asked for. Currently the standard proposition is to set $g_bug_readonly_status_threshold and $g_bug_resolved_status_threshold to large numbers (larger than the largest issue state value). This kind of works but messes up the my view page since this page refers to those thresholds when filtering issues.

One more thing, sorry for spamming, but things come to my mind step by step. I still have $g_bug_readonly_status_threshold set to larger than the state value of CLOSED issues such that EmailReporting can add notes to closed issues. This should be mentioned in the plugin's wiki page and maybe at the configuration option, too.

I believe the readonly threshold is already mentioned on the wiki page. I will have look at your changes sometime soon.

Changes applied to 0.11.0-DEV

That's great. Sorry for asking dumb questions: shall I create a changelog entry and if yes, how do I do it? Opening another pull request and changing the docs/CHANGELOG.txt? Or is it generated from the merges?

Already added it last week.
It's a manually created changelog entry

https://github.com/mantisbt-plugins/EmailReporting/commit/fbc4625b318248846eccb9c6d693f0450289338b