If you're an enthusiastic succubus researcher, there is good news and good news for you. No bad news at all. Yay! ːheart_of_succubusː
The first piece of good news is that Succubus Research Diary will get still get at least two more free content updates. The next update is coming out in early September!
September 6, 2022: ːstar_of_masteryː Version 1.4.0: An Old Friend ːstar_of_masteryː
The release date (or even month) of the fifth content update, however, is still yet to be decided, because it will connect the story of Succubus Research Diary with the yet-to-be-announced next Arcus Plume game. The update will probably come out shortly after the announcement of the new game.
The second piece of good news is that Serena and Nerisha will make their appearance in the above-mentioned next game as well! Not as major characters, though. ːwing_leftː ːwing_rightː How do they end up in that game? Play the upcoming updates to find out!