EasyMesh R1.5？

Could you please tell me whether the EasyMesh protocol used in the Archer BE900 and Archer BE800 routers is R1 or R2?

The packaging label and the hardware label on my TP-LINK Archer BE900 router both indicate Ver 2.6, but both the Tether app and the Web management interface display V2.0. What is going on here?