Mohammad,
To answer the original thread I do not tend to update them, but if I find I need to, first I drop the new version on a plugin tiddlywiki, where I can also add additional notes against a plugin (non destructively). I then typically drag from my "plugin tiddlywiki". There are far more plugins outside these libraries than in them. I would use the library method for ones I know about as you give as an example, however there is still a complexity barrier to regular plugin authors generating their own libraries. If a plugin to generate zip files of filtered tiddlers in library we would have more people using this mechaisium.
If I had this library building tool I would publish my plugin wiki collection as a library. I would use your published library to ensure your plugins are up-to-date and replblish them in my collected library and invite authors without their own published libraries to inform me if I do not have their latest plugin.
I would also start publishing more of my own materials in a library.
Tones