Players could receive the Alumni Jacket in Club Penguin Island by pre-registering to the game with their old Club Penguin nicknames.
The number on the back of the jacket showed how many years the wearer's account has been active, at the time of obtaining the jacket. For instance, a player with an account that is 2000 days old received the 5 year variant. As there is no 0 variant, players who joined less than a year prior to obtaining the jacket received the 1 variant.