Starting with next year’s Fall Regionals, day 2 of each tournament will feature an extended format of Black and White-on. This means that the first day of Regionals will be whatever the next Modified format is (once it is announced for next season), and then day 2 will be backtracking to allow for older sets that weren’t even legal this season. Presumably, other tournaments next season will feature the extended-format for top cut rounds. The news of an extended BW-on format was first announced last July.
If you make it to day two, this means you’ll be seeing cards like Eelektrik from Noble Victories again (and Tropical Beach, which will likely be rotated out at the end of this season). It is assumed that players can modify or change their decks between day one and two, which has never been allowed in the TCG’s history before, but full details are not yet known at this time.
This news also means that players will need to test for a wider range of decks and figure out how to change their decks based on what they’ve seen at their tournaments on day one. This will insure that the best player wins!