At the time of the writing of this post, the current version of OBS is 29, resp. 30 is about to be released in the near future. If upgrading is a burden for you, you should upgrade to the most recent version. Not so some already obsolete one.
The last time a major plugin upgrade was required (every single plugin required an update!) was upgrading from 27.x to a higher version. Old plugins stopped working, were deactivated and needed upgraded plugin downloads. Since then, the plugins didn't need any upgrade. Whether there is a plugin upgrade required from 25 to 27, I don't know. Look into the release notes of the corresponding releases.
I recommend this:
- if you're running OBS 27 or earlier, uninstall OBS and every plugin to avoid any mixture between new OBS and incompatible plugins. Take note what plugins you used. Then get the most recent version of OBS and install it. Then download the most recent version of the plugins on your list and install these as well. If you have a plugin that doesn't have a release supporting OBS above 27, that plugin can be considered obsolete and abandoned, and you should find an alternative.
- if you're running OBS 28 or later, just update OBS. It's recommended to check every plugin every once in a while and see if there is an updated plugin available. Outdated plugins are one major source of crashes, so you should seek for keeping everything updated. As far as I know, there's no plugin manager for OBS that does this housekeeping, so that's always some manual work.