Question about Firmware Update to EF 100-400mm f/4.5-5.6L IS II USM

[Wandalynn]

I had seen in another post about a firmware update for the EF 100-400mm f/4.5-5.6L IS II USM (which I discovered  the previous 1.0.6 version on mine). I hope this isn't a dumb question but can I do the update via an RF to EF adapter on my R5 or R6ii? 

[shadowsports]

Excellent.  I did 3 lenses last night and actually reviewed the update procedure.  It does change depending on your hardware.  I noted this.  ➡️ OK to use supported mirrorless body to upgrade EF glass with EF to R adapter.