Always use the most recent version available as stable or latest in ioBroker.
There will be no support for outdated versions.

If you identify a vulnerability, please consider that this may affect other people/projects as well. This in mind please email me (Yannic Labonte yannic.labonte@gmail.com) first, so I can react and maybe fix the issue, before it is published to the public (e.g. in a github issue) and maybe misused by third parties.