@Bolton-UK funny (or not)... When I bought my Deco M5 I firstly wanted to use them in AP mode and found there were very strange bugs, it looks routing mode is more reliable and you confirmed this...

@Bolton-UK Finally I tried and succeeded in updating my four Deco M5 v3 (fr) to 1.7.5 using the web interface. All the Deco have been updated, this update has a very strange behavior in your case.

@Bolton-UK maybe we should wait for communication from TP-Link, which does not look very probable in fact. I am really hesitating about trying to install it.

@Bolton-UK I checked on US and French TP-Link website and it was not, so things become very strange :) OK, In France I was mistaken, it is available. Maybe it is specific for EU?

@Bolton-UK no. And after a verification, it is the same for v1, I have not found any firmware version 1.7.5 for Deco M5, last is 1.7.4.

@budgie29 On TP-Link website there is no 1.7.5 at all for v3 so it is possible it is surprisingly only available for v1.