Forza Horizon 4 is due an update this week to Series 23, and the reveal was originally slated for June 1 on the Forza Monthly stream. As part of a company wide initiative at Microsoft that stream was cancelled and all media activity along with it, but the actual update itself is still planned as normal.
The Forza Support account on Twitter has confirmed that it’s still planned but it is delayed, since players would have expected it to have been released by now:
We have identified an issue with the Series 23 update which has caused a delay in release. We will keep you updated once we have more information. #ForzaHorizon4
— Forza Support (@forza_support) June 2, 2020
That’s all she wrote for now. The support forums still have no patch notes so we don’t have any idea what’s actually coming in the update, but it looks like it’s still coming, at least.