Just a quick update on this.
Last night I did a more extensive troubleshooting on this. I used the WiFi Analyser application on my phone to check how the channels are used, and boy, it's quite crowded! I changed the channel several times with very little improvement of the overal packet drops, so I settled for the last available channel at the very end of the spectrum - 13. The improvement is tangable:
1. The response times have improved considerably. Now the average rtt is about 2ms. Maximum rtt around 50ms.
2. The packet drops are up to 3%
And all of this figures I've got after extensive pings overnight, to get a more statistically sound result.
I don't think that the software upgrade is to be blamed, it's more or less a coinsidence that after the upgrade new noise sources were available.
I still want to improve the figures though. I belive that the packet drops should be below 1%, or maximum 1%. In order to achieve that though, unfortunatelly I have to reposition the router
Right now the router is in the doorway, right above the front door of my appartment. I could move it closer to the center of the appartment and the end hosts, it's about 5 meters.
Could you guys comment on what kind of a performance you have in your home WiFi environments? I'm interested to see whether the goal I'm setting 1% packet loss or less is achieveable. I hope it is