Correct. The last Development Livestream was in July. There has been no announcement on the date of the next one. The date of the next livestream is usually announced in the Development Update blog that precedes it. These blogs are posted in Official Microsoft Flight Simulator > News & Announcements
The Community Managers also host Fly-in Livestreams, such as the Community Fly-In Friday, such as this one from last week, but these are not designed as Q & A sessions about MSFS.