I'd like to ask. Are their improvements present in 17.01 kernel 4.4 ar71xx ath9k build ?
I believe at least some of them are.
Improvements to the WiFi stack eliminating bufferbloat on ath9k, mt76 and some ath10k chipsets
Check out LEDE v17.01.0 final release notes.
improvements compared to what? compared to OpenWRT CC, yes very big
Is it worth upgrading from early (year ago) openwrt dedicated driver to lede 17.01 ? Will it bring any advantages to pure wifi access point ? If yes then is it enough just upgrade or need some sqm configuration to enable cake or something else ?
I guess it's advised to do a clean upgrade and to not keep configs. You should configure your router again manually, based on you backup (you should make backup of your current configuration every time your upgrading) because some of the settings between OpenWRT and LEDE are different.
It probably will but I haven't tested this myself. My thinking is LEDE came a long way after OpenWRT died and more new innovating features and fixes were introduced. On what device do you want to do the upgrade? LEDE is NOT recommended to be installed on devices with only 32MB of RAM and 4MB of Storage.
I'm on WNDR3800.
I already did upgrade but do not know if it changed anything. Speed with 1 wireless client is the same.
Check out this thread. Some users are claiming significant WiFi performance boost.
To learn more about the Airtime Fairness/Bufferbloat fixes that are in LEDE, check out a nice overview at: https://phys.org/news/2017-02-smarter-routers-latency-internet.html
Or read all the details in a preprint of Toke Høiland-Jørgensen's paper at: