AnyVersion is a plugin that allows your players to play with older clients. This plugin is more than a protocol version bypass. It actually translates newer packets to older clients (vice versa).
Please be aware that this plugin has to be updated with every new minecraft version. Even though this plugin allows players to join with versions down to 1.19.70, we only offer support for versions down to 1.20.3. This is because on versions below, custom blocks are not longer translated. For version below 1.20.0, you cannot even connect anymore without disabling xbox auth. And on 1.19.70, there were no BlockHashes, which PNX uses. Therefore dont expect help from us when players with clients lower than 1.20.3 have problems on your server. (Thats old enough anyways)
If using WaterdogPE, you probably want to use SyodogPE. AnyVersion works with base WaterdogPE, but your WDPE console might get spammed with some warnings you can just ignore.