The latest upgrade to the 1500 was in 1996. I can't remember what all the upgrades were, but I do remember that is when they changed the alternater. I had a web site that told about the history. I will try to find it for you.Are there any major differences between the first year and last year they made the 1500? I have a 1200 Aspenccade now, and am thinking about trading up to a 1500.