The release date of The Elder Scrolls 6 was discovered in the Microsoft and Activision Blizzard deal documents

The only problem is that the data was not made public — so far, only the Competition and Markets Authority knows the game's release window

The Competition and Markets Authority learned the release window for The Elder Scrolls 6 ahead of insiders and the press. The information became available to the UK regulator as part of its investigation into the merger between Microsoft and Activision Blizzard. 

One of the documents contains a section dedicated to a “mid-sized” game titled The Elder Scrolls 6, whose release “is expected no earlier than [redacted]”. Therefore, Bethesda already has a planned date, but the company still managed to persuade the regulator not to spoil the surprise.

However, you should not expect the game to be released anytime soon, as Bethesda promised to launch Starfield first. Head of Xbox Phil Spencer also stated that The Elder Scrolls 6 would only be released after Fable 4.