With the rotate of Dragon’s Maze, all sanctioned formats as well as the group that oversees the Commander format announced their updates to banned and restricted lists.
The following changes are:
Standard, Extended, Legacy
Regrowth is unrestricted.
Second Sunrise is banned.
Staff of Domination is unbanned.
Trade Secrets is banned.
Functional Errata and Relevant Rules Changes
Gaze of the Gorgon, Glyph of Doom, and Venomous Breath apparently had some kind of timing glitch that technically allowed you to cast them after combat and last into the next player’s turn. This was corrected to match their actual intent.
The only notable rules update pertains to split cards. Previously with cards that made you name a card like Meddling Mage or Runed Halo, in order to ‘capture’ a split card, you had to name both sides for it to count, and in the cases of preventing it from being cast, it would lock out both parts. This is no longer the case. Now, naming one side prevents that side only from being cast, but the other is still legal. That said, if one side is locked out, split cards with the Fuse ability can no longer be fused.
The explanations of the non-Commander Banned & Restricted changes can be found here.
The Commander announcement can be found here.
The full list of rules clarifications can be viewed here.