50000

50,000 was ostensibly the year in which K9 Mark I lived immediately prior to journeying to the year 2050 and "regenerating" into K9 Mark 2.
During this year, the Jixen were driven to near-extinction, leaving only four individuals. (TV: Hound of the Korven) Also, Zanthus Pia was assassinated by Ahab, the bounty hunter, under mysterious circumstances. (TV: The Bounty Hunter) Ahab himself died in this year when he returned from his unsuccessful mission to capture K9 in 2050. He apparently suffered from asphyxiation before he was dragged into a supernova. (TV: The Bounty Hunter)