If you are a user on beehaw.org, please let your instance administrator know.
In addition, if you are on a very small instance, please check that it is running lemmy 0.19. You can do so by going to the community list -> header ellipse icon -> instance sidebar -> version listed at end of instance statistics.
This deadline will only be extended if lemmy.world is unable to upgrade by March 18.
If you are self-hosting Voyager, you can continue connecting to a v0.18 instance past this date by staying on Voyager 1.x (I will be dropping lemmy 0.18 support as a major version bump).