The official website of the anime Nanatsu no Taizai, adaptation of Nakaba Suzuki's manga, has announced that its fourth season, Nanatsu no Taizai: Fundo no Shinpan, scheduled for release in October, will be postponed due to the effects of the new coronavirus (COVID-19).
At the moment, there is no official announcement of when the fourth season will be released, but when the production committee decides, it will be announced through the official website and the official Twitter account.
The third season of the anime ended on March 25th and is scheduled to hit the Netflix platform in July under the title "The Seven Deadly Sins: Wrath of the Gods".
Source: Official website