You can probably leave it as your old address......They will use the mailing address that is on your tax return...just as long as some family member of yours still lives there.
That former address (if that is on your tax return) is where the IRS will send questions that you MUST respond to...and if the IRS encounters any problems with sending your refund,, it will also be where any paper check refund will be sent. So a family member should be living there that can contact you immediately.
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Or explain further about what's up.