I am currently browsing the page (identical to JA 3) "Knights of Honor II: Sovereign" and the first Dev Diares were released on December 10, 2019, the second on January 7, 2020 and the third on February 4, 2020, i.e. one Dev Diary every month. There are 22 of them at the moment.
https://community.knightsofhonor.com/index/dev-diaries/