AirVPN: IPv6 only vs IPv4 only but not both?

[ohshitgorillas]

URL to the Wiki page

https://github.com/qdm12/gluetun-wiki/blob/main/setup/providers/airvpn.md

What's missing?

First, from the AirVPN config page:

⚠️ WIREGUARD_ADDRESSES may only contain an IPv6 address (such as ff:ff.../128) if your container setup supports IPv6. To do so, see the IPv6 document. Otherwise, remove the IPv6 address from WIREGUARD_ADDRESSES.

And second, from the IPv6 page:

Wireguard: modify the WIREGUARD_ADDRESSES value to have both an IPv4 and IPv6 address. Note if you only set an IPv6 Wireguard address, all IPv4 traffic won't go through which is undesirable.

Does this mean that gluetun either only supports IPv4 or IPv6 when it comes to AirVPN, but not both?