Originally Posted by
MePlatPremier
all pending reservations when the platform migration took place were assigned a new reservation number. don’t know if that’s the case with OP’s booking.
Which platform migration?
There was the website platform migration on Aug 18, but then there was the brand-specific hotel-side reservation platform that migrated at the end of October for Sheratons but I don't know when offhand for other SPG brands.
My Sheraton reservation numbers stayed the same (or at least the last 4 digits did) from my pre-Aug 18 bookings to my post-Aug 18 stays, at least for those stays before the end of October.