Yes, IPv6 is fully supported by EuropeanMX.
If the IPv6 addresses were not known when you set up your cluster, please inform our support team. We will be happy to add the addresses to your configuration. Please ensure that your server host name points to the primary A entry (1) and contains all AAAA entries (1 or more) for the IPv6 addresses.
To avoid compatibility problems with bad IPv6 senders, we strongly recommend that you always use an MX record without AAAA.