Invalid decks in standard
Since the Wilds of Eldraine update, my standard decks have turned to be "invalid". I have found out that the troubling cards are those of the 4 older sets of the format: Streets of New Capenna, Kamigawa: Neon Dynasty, Innistrad: Crimson Vow and Innistrad: Midnight Hunt.
When I am to select a deck,a yellow triangle sign appears, saying I have a certain number of "non format cards". When I open it, it suggests that I change the format to alchemy. It is only then when the cards that are suposed to be "not valid" are highlighted in red. The deck is also not valid for alchemy, by the way.
As you may see, since no sets rotated out this year in standard format, my deck should be valid.