v18.5.1-MR1 - Where is Sophos DynDns *.myfirewall.co gone?

Hello together,

does anybody know, if it is intended, that with v18.5.1 MR1 Sophos dyndns service is not listed anymore?

Sadly, our standard enrollment for branch offices relies on Sophso dyndns (*.myfirewall.co) for establishing a route based vpn connection to our head office, because with routed based VPN a "wildcard-character" for the initiating remote firewall ip is not supported and we have no static IPs on our 50 branch offices, thus dyndns is our only way to get all branch offices connected to our head office firewall.

Afaik comes a right to use Sophos dyndns with every Sophos license. Was this changed and if so, where can I read an official statement?

https://docs.sophos.com/nsg/sophos-firewall/18.0/Help/en-us/webhelp/onlinehelp/nsg/sfos/tasks/NetworkDynamicDNSProviderAdd.html 

Or is it maybe just a bug and Sophos forgot to implement their dyndns in v18.5.1?

Any suggestions, which of the dyndns services listed below can reliably be used to register 50-100 dyndns records for free? Maybe we migrate step by step to another dyndns provider...

An additional thing that comes to my mind.

What if I upgrade the software on our 50 already running branch office firewalls configured with Sophos dyndns service? Will they have any issues? Will my dyndns config just be deleted or is something even worse gonna happen?

Thanks in advance for all helpful answers!

Kind regards,

David