https://www.vox.com/culture/23589595/rick-morty-justin-roiland-dan-harmon-save

Justin Roland, who voices both Rick and Morty, is no longer associated with the show as a result of domestic violence charges against him. Rick and Morty is continuing, but it's unknown how they'll handle missing their main voice actor.

Resolves YES if the first full episode of Season 7 of Rick and Morty contains an in-story reference or reason for why either or both of Rick and Morty have different voices than before. 

Resolves NO if there are no references to the new voices (this includes a scenario where they don't mention it because they manage to make the new voices sound near exactly the same).

Resolves N/A if Justin Roiland voices both characters again.

This could be as simple as an off-hand reference to Rick having developed a new cough, or Morty having started puberty and "going through changes" or something. It doesn't have to explain the new voices, just make a reference to the change. I plan to be pretty lenient about what would count as a reference, but it should be reasonably likely that it was included intentionally by the writers with an intent to reference the voice change.