Tesla is calling it a Retrofit.Mostly people who have "fit" new stuff into their "retro" things, but I get where you're coming from.
Text from my invoice.
Concern: Full Self-Driving Computer Retrofit (Model S and Model X Group 1)
Removed vehicle car computer and installed HW 3.0 computer. Performed configuration change to vehicle and updated
firmware. Performed forward facing camera calibration and verified on test drive vehicle is operating as expected.
Correction: Full Self-Driving Computer Retrofit, Model S (North America Only)
Parts Replaced or Added
Part
ASSY,AUTOPILOT.ECU,3.0-MSX-FUSED(1655000-70-F)