From the proposed March schedule revision with more E7 sets entering service in Joetsu Shinkansen (which was delayed due to losses from flood in Fall 2019) the E4 Series EMU will officially retire from services in Fall 2021.
Some in-train service changes:
1. Prices for Gran Class services for Hayate and Yamabiko, which have no light snack + drink services will be reduced by 2,090 Yen
2. Certain Kagayaki and Hakataka services will no longer have in-train sales, more details will come when JR East releases the March schedule revision
3. All Inaho and Kaiji services will no longer have in-train sales
https://www.jreast.co.jp/press/2020/20201218_ho04.pdf 