Save a copy of the mdl and whatever comes with it to your usermod, because the next changes might damage existing sessions. I would rather not change that much, but everyone requested various changes, including the collaborator.

The stuff that needs to be copied is: everything in workshop/models/props_invader and everything from workshop/materials/models/props_invader
So copy the entire folders and move them to the corresponding folders in usermod or whatever custom folder you have.

EDIT: Update news can be found here: http://gtm.steamproxy.vip/workshop/filedetails/discussion/534376954/490123727972749124/