OPEC+: Next JMMC meeting will take place on 4 December

That will come just before the OPEC and OPEC+ ministerial meetings

Just be aware that this is standard protocol for the JMMC meeting to take place right before the "main event" in Vienna. As of this moment, the next OPEC meeting is scheduled for 5 December while the accompanying OPEC+ meeting is scheduled for 6 December.