This will work for existing users. As long as your membership has expired and there is no active subscription left on your account.
If you have a current ultimate membership, please wait until it expires before activating another code.
If you have game pass core you can use this to convert core to ultimate.
You must have a valid payment method on the Xbox account, (A payment method is required to activate the membership, you can switch recurring payments off as well as remove the payment method if you wish after activation).
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