For many years now, IDN has been a natural part of most domaintypes.
For Whmcs the integration of IDN has only started, causing many problems for clients that actually sell IDN related products every day.
The latest response from WHMCS, after we had faced a problem with IDN registration of a simple .COM domain name, was:
"Regrettably IDN are not supported by registrar modules in WHMCS at this
time. Each different registrar has implemented IDNs in a different way
and we need to find a way that is compatible with all of them, which is
proving quite a challenge.
However this is a problem we are always looking for a solution and hope to have implemented at some point in the future."
That response is simply not good enough as we had an almost similar answer 3-4 years ago...
Presently an IDN order through Whmcs even causes misregistrations where Whmcs interprets the punicode wrong and then simply registers a completely different name than wanted and not even a punicode name, leaving you with registred domainnames that are to no use at all...
The least Whmcs could do was to throw such an order out to manual registration instead of just registrering some completely different names than the actually ordered..
Give this the HIGHEST priority - Whmcs clients are having losses and problems because of this BUG in Whmcs.