The closed beta session of Wizards of the Coast's Magic The Gathering Arena computer game will begin in December 4. WotC says the close beta will begin small with features and content being added as it progresses.
Not everybody who signed up for the closed beta will have access right away, however. Only those who signed up and participated in the Ixalan pre-release event at a local gaming store will be let in. All others will have to wait.
"We intend to start inviting players who have signed up for the MTG ArenaClosed Beta without priority access at some point in January," says WotC via email. "The exact timing will depend on our development progress, but we'll get you in the game as soon as we can."
No solid release date has been established for Magic The Gathering Arena. As WotC says on the game's FAQ's page, "It will launch when it's ready."