Pre-orders are moving by Fedex from B&H as we write this. The heir to the Canon EF 100-400 II is making its way out to grasping hands only hours after Canon included an image stabilization integration improvement in the R5 firmware.
Camnostic should have a copy in-house for testing by end of day tomorrow, with two R5 bodies (one with old, one with new firmware), an R and an RP. Canon’s online store reports that they are in stock.