Pretty much all the mainframe manufacturers (IBM plus the BUNCH - Burroughs, Univac, NCR, CDC and Honeywell - ICL didn't appear because this was US jargon!) did this.
The upgrade kit to turn a DEC VAX 82x0 into an 83x0 consisted of the digit 3 to put on the front panel and a set of microcode EPROMS containing fewer NOPs. One of the other VAXes required only a backplane jumper to be (re?)moved.