Apple warns developers that App Store Connect will be on vacation December 23-27, 2020. This means that developers cannot submit new apps during this period. This also applies to sending updates to existing applications. This also affects the prices, which cannot be changed.
This interruption does not mean that there will be no new apps or updates in the App Store from December 23-27. In fact, developers can request to validate their application before December 23rd and schedule availability later. It happens from time to time.
If previous years are an indicator, then several app promotions will be offered in the App Store before December 23rd. They will persist until App Store Connect reopens on December 27th. Apple said in passing that the various tools will still be available to developers between December 23rd and 27th.
No commission until June 2021
In addition, Apple mentions the case of online group events (e.g. classes). They are becoming more and more numerous these days due to the Covid-19. Apple typically receives a 30% commission when this type of event takes place in apps. Apple had announced that this would not be required until December 2020. Today the manufacturer announces that no commission will be charged for these special cases before June 30, 2021.