When a team agrees to purchase another company's engine to use as their own, as Red Bull have done with Ferrari, what is the engine supplier's obligation to the purchasing team? Is it simply to provide an engine at the beginning of the year and that's it, or is Red Bull entitled to subsequent engine updates?
Team that buys engines gets engine technicians/personnel from manufacturer. Original team members can't open or mess with the engines.
Also, even if no evolution of engine is planned team doesn’t gets all engines at the beginning of the season because engines would face corrosion and since they can't be conserved they are manufactured and assembled trough ought the season.
Basically, teams only pays for using the engine because they are never free to do with them what they like and they can't keep used ones unless manufacturer gives them some (mockup engines for shows or actual ones after they become technically aged). So, it is a lending with constant supervision.