Rotate DKIM Keys in Microsoft 365: Two Rotations to Reach 2048 Bits
DKIM was enabled on your Microsoft 365 domain years ago and the keys have never changed, probably at 1024 bits. This walks through the selector swap, the exact PowerShell and portal steps, the 96-hour changeover, the two rotations needed to reach 2048, and the third-party signers a rotation never touches.