@MojangSupport If I have a Minecon cape code I have been saving for some time, but am worried I have been hacked and it has been used, is there any way for me to confirm the code is still valid without actually attempting to use it?

Try to redeem it on an account with a Minecon cape, if it’s a 2016 cape and the account that you’ll use the code on is a 2016 too, it’ll say « Cape already owned »