So first of all what is 'DNS Flag Day' you ask.
Well from 1st February 2019 the old system that was used by DNS servers was deprecated and a new improved system came into use.
Basically the software makers of the most common DNS resolver software have been implementing a patch like system to these software services for years and now this will stop and each DNS Server is from now on going to be forced to use the new packages.
This should bring all DNS servers into line with the RFC and stop all the non-standard responses when looking up a zone file record.
The good news is - that for 99.999999% of the users of the internet for now you will not even see that anything has changed and I would expect this to continue to be the same for quite sometime. However, we at redIT operate three DNS Name Servers for all our registered domains and we have got all but one fully compliant with the new standards. We now plan on removing this server and bringing a new one online by the end of the year this will also be in a new data centre location which will give us more redundancy for our DNS Service.
If you would like to know more about the DNS Flag Day please have a look at the following links: