What is the X in X-mas?
1873, "upward slope," from up + grade. The meaning "upgraded version" is recorded from 1980; the verb in this sense is attested from 1920 (implied in upgrading).
1. A new or better version of some hardware or software. Often used in marketroid-speak to mean "bug fix". 2. The act of developing or installing a new version. (1995-03-14)