You can now spark for units on the summon banners. You should have received any sigils corresponding to historical summons on the new banners (since mid-March). The first two unit and dragon banners have every permanent and gala unit and dragon available for sparking. The remaining limited banners have their limited units available to spark.

As you hopefully realized, the message below was an April Fool's joke. Elisanne has been re-added to the game; it was purely a visual trick so there should not be any data loss.

Elisanne and her alts have been removed from the game. She is attending a workplace sensitivity training and will be back soon. If you had her as a leader in any of your parties, please select a new leader before attempting any quests.

Dawnshard now has accurate summoning rates instead of ludicrously high five-star chances. There are also multiple banners to choose from - a general gala unit banner (Euden/Zethia), general gala dragon banner (Zephyr) and then various seasonal / collab themed banners which can give rare units. I am currently only able to use banner images from the original game, but some may have not-displayed units on focus, so check the appearance rates screen on each banner for the most accurate information.

Endeavours have been added to the Mercurial Gauntlet. You should have missions pre-completed for any levels that you've already cleared when you log in. To view the list of available endeavours, click the 'View Endeavours' icon from the Mercurial Gauntlet menu, which should bring you to a (slightly hacked together) page with the infographic.