No date announced yet. The new PV is here. The announcement comes after the third season finale aired today. Check out the Crunchyroll article for additional information. Synopsis of the source novel series from AniList:
The year is 2095. Magic has been tamed as another form of technology, and the practice of magic is now a rigorous discipline. Brother and sister Tatsuya and Miyuki Shiba are just about to start their first year at the renowned First Magic High School of Japan. But the school’s ironclad rules mean that the brilliant Miyuki enters the prestigious Course 1, while her older brother, Tatsuya, is relegated to Course 2–and that’s just the beginning of their troubles!
I need to catch up on this. I recall really enjoying the first season.
Second season wasn’t that good in my opinion but the movies and the third season where so far.