A bit of warning to WHMCS users that were hoping to implement the New TLDs that reached general availability this week (.bike, .clothing, .guru, etc.):
Despite all the work and promotion going into the pre-order process for the new TLDs, WHMCS (even version 5.3.3) does not currently support them now that they are in general availability.
The whois.donuts.co whois server can be easily manually added, but what has been discovered is that some domains have premium pricing, so say you setup WHMCS to charge $30 for a .bike, you may find that a customer orders a premium domain that you charged $30 for that actually costs you $250. So you may want to process orders manually if you plan to offer these domains immediately.
WHMCS has confirmed that support for detecting premium domains is not available. The eNom API has the ability to check for premium domains but this has not been implemented so modules will need updating.
I'm pretty shocked that support for the new TLDs weren't implemented long ago, but if this is a concern to you, it would be great if you could upvote the feature request.
What's ironic is that, among all the addons, the ONLY one that did not work after the WHMCS v6.0 upgrade was the NewTLDs from eNom. The New TLDs Addon is built and maintained by WHMCS. I plan to open a ticket with them to see if their will be a future release for version 6 compatibility in the near future.