With Revision 0, the REVID was changed from 0xB0 to 0xB1. This corresponds to the release of the part.
With Revision 1, REVID was increased to 0xB2.
With Revision 2, REVID was increased to 0xB3.
Then with Revision 7, as stated in the datasheet, REVID was increased to 0xB4 and is currently 0xB4.
(Latest datasheet released 2016. Still applies at the time of this writing: 3/19/2021)