I'm not having any problem with the speed. It's an issue that drops the Wifi connection for a few seconds and doesn't work then at all. It doesn't even join the network as well so I'll have to turn it off and on to connect. Strange it is, I tried to connect to the main router which is in the living room and surprisingly, it works pretty fine! Works like a charm with no Wifi dropping signal or connection. Except the access point that doesn't work. Even tried changing the frequency and channel to 11 from 6. Still the same.
Seriously I don't think this is software mate. If it was software then it just wouldn't work instead of working some of the time.
This could all be coincidence that the problem occurred at the release of this iOS version. I've had issues in the past where everything worked fine for years then suddenly started dropping connection. Turned out someone had moved in nearby and was using the same wireless channel as me and causing interference meaning my iphone was unable to get a clear wifi signal so would struggle! I've also had a mate who had the access point setup without s static IP outside of the Dynamic IP range so would constantly drop the connection due to conflicts. Perhaps you have a new device that is causing the conflict.
Have you tried switching off every other wifi device within range and then seeing if it still drops?
Also you could assign static IP addresses to each device connecting to that AP to ensure no conflicts.
Also on your laptop or perhaps there's an iOS app but run a prog/app that shows which wireless channel the routers within range are running to see how many are showing up. Remember to make sure you are a min of 2 channels away from the others for best results as wifi channels overlap.
Obviously make sure your AP has a static IP assigned to it from your main router and that the IP isn't within your main routers dynamic range. I'd also forget the main router from your iOS devices so that it doesn't keep trying to swap and connect to the main router if you're nearer!
People suggest disabling the 5ghz network but I'd not do this as the iPhone's now use both and by connecting to the 5ghz network you're then able to connect on a much larger number of channels with means much less interference.
Also if you're using the 5ghz on your iOS devices I'd ensure you've forgotten the 2.4ghz network if you've also connected to that in the past so that it doesn't try and swap between the two.
Let us know how you get on!