- does OpenWRT support WPA3? Yes, for official release, since 19.07 with wpad-openssl. wpad-wolfssl has been fixed in master/development
- does it require special hardware? No AFAIK
- any negative issues (like lower performance on older hardware)? In my test case no, the WLAN speed seems to be CPU-bound even without encryption, others with more experience may chime in?
- a word about compatibility with other devices (like the mentioned Apple issue) You can go ahead and add later when people report other incompatibilities
- is mixed WPA2/WPA3 really more secure than just WPA2? I read that exclusive WPA3 is better, but forgot the details. see reply of huaracheguarache
- is WPA/WPA2/WPA3 mixed mode possible? (I see no support for it currently, but what in theory?)
no idea, but why would anyone still use WPA?
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