The revision ID of the MAX30100 is primarily there to identify the silicon/metal revision of Maxim's MAX30100 device. Thus, it can be used to help Maxim track reported field failures and match a failure to the silicon/metal revision. The Revision ID will not change unless there is some significant business case. As of the writing of this FAQ, there has only been one revision ID released and shipped so far, REV_ID = 0x05.