This should still work on Minecraft accounts that were created 5 minutes after Notch first launched the minecraft.net website in 2009. You will use your username to login, but a verification email will be sent to whatever email you signed up with. If you don't remember which email you used, you might be out of luck, but they also have a support form where you can enter payment proof and maybe get the account back. All of this is ending in September, so take this opportunity soon to be able to talk to an actual human at Mojang rather than a useless robot at Microsoft/Xbox support.
A gift code will present significantly more trouble. Almost certainly not valid anymore.
I wonder the same. I bought an extra code back in alpha because Notch promised it'd grant all future versions of the game. I wonder if it will still redeem as a valid code after two different system migrations (Minecraft account > Mojang account > Microsoft account).
I successfully migrated my Alpha account. I did it back when they first turned off the Mojang authentication server. It was an absolutely awful experience, but in the end I'm able to log in to Minecraft using the Microsoft account.
Yup. I did this about a year ago. They had actual humans, who can read and understand, but they didn't seem to necessarily have all the pieces of the puzzle and Minecraft is very old, so there was some amount of (fake examples but similar):
Them: You should have a sixteen digit Game Token from your purchase
Me: I don't have a Game Token, I think those were introduced six months after I bought Minecraft, I have an eight letter Login Code, it's FKLEMOKN
Them: I'm afraid we can't trace Login Codes to a game purchase, do you have a Receipt Number?
Me: My PayMeNow Receipt Code was 1234-5678-LD-23
Them: I'm afraid we only have FastPayment Receipt Numbers, not PayMeNow Receipt Codes, do you remember your PayMeNow email address ?
Me: I used a lot of email addresses back then, maybe minecraftgame@throwaway.codes.example ?
Them: Maybe we can start with what was your Minecraft Foozle Weeble DingDong. That was a six digit code used for eight hours one Tuesday morning in 2016 ?
Me: That's the only Tuesday in 2016 that I didn't play Minecraft, but I do have a Wongle Dongle BingBong if that helps?
Eventually I just basically flooded them with stuff and they were like "Good enough, you're in" and so I'm not sure which of the random facts I had were enough or whether they just decided this guy seems really into Minecraft, and he is named tialaramex, the same name as the account so, I guess it's probably him.
