"A number of DNS software and service providers have announced that we will all cease implementing DNS resolver workarounds to accommodate DNS authoritative
systems that don’t follow the EDNS protocol. Each vendor has pledged to roll out this change in some version of their software by the ‘Flag Day.’"

Voir aussi: https://www.afnic.fr/fr/ressources/blog/1er-fevrier-2019-le-dns-va-t-il-trembler.html
et aussi: https://dnsflagday.net/