RTS has announced that they will halt the release of new Season 4 episodes in order to air them in order (take note, Gloob). They said they will continue when more episodes are finished, giving a rough estimate of the beginning of Fall. Autumn begins in September, and that was the original planned date for Season 4 so this all checks out.
Keep in mind there could be more episodes that are finished between now and Fall meaning we will likely see those sooner because Gloob likes to go against our wishes.