Hi @Brez (and @LSEM) Yes the Weak Security message has gone from my iPhone. I'm having difficulty remembering how I got into the TP-Link Cloud management options but I'm pretty sure the instructions...

@dsenn have you tried changing the wifi security settings via TP-Link Cloud. That's what finally solved it for me.

@DaveFromBoca I have been experiencing this problem (iPhone reporting weak security) with an R350 V3.0. It has now been resolved with the latest Firmware and managing the device through TP-Link Cloud...