Since the release of Season of Mastery on November 16, 2021, World of Warcraft Classic enthusiasts have been chasing down Zhevras for their hooves and plucking the feathers from Fleeting Plainstriders.
Blizzard announced in a blue post on the official forum that the Enter World button for all SoM servers would be disabled. The only option you'll have is to transfer to Classic or Wrath of the Lich King servers. The transfers will be free for all players who wish to continue their Classic journey.
The developers did not disclose how long transfers would be available, therefore they strongly advise you to transfer your character as soon as possible, especially if you became inseparable.
As the developers promised to keep your characters alive, you may also choose to leave your character on the SoM servers. However, if you grew fond of your character and don't want to lose all of the progress you've made, you should consider transferring your character.
As you pack your bags with tears in your eyes, we have to inform you SoM will most likely return later this year in even better shape. Until then, you can explore the Dragon Isles, join the hardcore community of Classic servers, or assist raiders defeat Yogg-Saron in WOTLK Classic.