I don't understand what you are saying.
The Creative Cloud software defaults to removing old versions of software when installing new releases as detailed here. If you would like to install (or re-install) older versions, you can do so easily with the Creative Cloud app. Instructions for that are detailed here.
If you are talking about third-party plugins. You will want to use new installers provided by the companies you bought them from to use in the new version of After Effects or you can manually copy them over from the older version. (But the new installer would be a better idea.)