Import ratio

Could someone explain how the import ratio works this year now that we are allowed 46 on the roster but only 42 can dress? Can the "extra" four be all imports, all non-imports, or a mix? Is it still 20 non-imports, 19 imports and 3 QB in the 42?

Is it still 20 non-imports, 19 imports and 3 QB in the 42?
That would be correct, meaning that four imports have to sit out on game day. Teams have up to an hour before game time to decide which 42 players will dress for the upcoming game.

Many thanks.