This issue maybe linked to JRA-10733 : I have just realised that most of the plugins we are using in JIRA have been already updated several times by the developers (i.e. there is at least a new version of the plugin available).
I am wondering if, in the plugins metadata you have, there is an information (e.g. a repository in internet, an URL) allowing JIRA server to verify periodically wheter new versions of an installed plugin are available and warn the jira-admin group consequently.

After that, obviously the feature requested by JRA-10733 would close the loop , allowing an easier update of the tool.

I am not asking something like Thundevird who has a dedicated pane able to verify if there are new version of the installed plugin, able to verify existance but also to download and install it "on demand" (it woulkd be a dream in fact) but at least an "obsever" who warns in case new versions is detected. An email containing which plugins have to be updated would be the minimum.