Yesterday we sent out emails to site admins who are still using one of the old IP addresses in their custom domain DNS 'A' records. It's been some time that ping wikidot.com returns the new IP address and now we're switching off that old front-end IP address.
Sorry for not announcing this before sending out the email. In any case it's trivial to check:
$ ping wikidot.com PING wikidot.com (188.8.131.52) 56(84) bytes of data.
EDIT by Gabrys:
Just to remind, to update your DNS settings, you need to either log into your DNS settings web service or locate the zone file for the listed domains. There you change the old Wikidot IP address (which may be 184.108.40.206 or 220.127.116.11) to the new IP address: 18.104.22.168. If using Bind or similar software, don't forget to update the serial number for the zone :-)