Quoting from the web site at
https://dnsflagday.net/
What is happening?
The current DNS is unnecessarily slow and suffers from inability
to deploy new features. To remediate these problems, vendors of
DNS software and also big public DNS providers are going to
remove certain workarounds on February 1st, 2019.
This change affects only sites which operate software which is
not following published standards. Are you affected?
On that web page, there is a Domain Owner's test. I have already
tested
AMPR.ORG, and it passes except for one test on one of our
secondary servers times out. I am working with the person who so
kindly runs that secondary server [in Thailand] to get this fixed.
Please don't run any more tests on the
AMPR.ORG domain.
But if *you* operate servers for a subdomain of
ampr.org, such as
'se.ampr.org', you may wish to test your subdomain and see if there
are things you need to fix. In fact, the "se.ampr.org" subdomain
does indeed have a few problems that probably should be addressed.
(In particular, it looks like the DNS server software for that domain
may not be listening on the IPv6 addresses for those servers.)
- Brian