You are, in fact, mistaken.
It was a massive overhaul for the game's code. Months of work, not a minor tweak. The entire sandbox portion of the interactions was reworked and a lot of it substantially re-written. Non-plot required interactions between Null and the girls will now rarely be the same twice as the new code draws from a massive pool of variables and applies somewhat organically. It not only adds a fresh dynamic to the game, but allows for seamless, extremely easy additional dialogue/interactions to be put in later, either by the devs or by modders.
Further, entire scenes and portions of dialogue in the game itself were added/re-written to accommodate different paths. A great deal of content was added to deepen the experience for those who chose to have a platonic relationship only with one of the LIs and assign full weight to the relationships with or without Quirks.
An entirely new aspect of the sex system was developed and implemented, so that the LIs become more experienced and learn different sexual techniques, etc over time and usage, becoming more proficient with them and entire new dialogue trees to accompany that.
A lot of optimization changes were implemented to smooth Live2D as well, allowing for smoother play, especially on Android.
New soundtracks for several scenes as well.
It's been a huge effort, especially by the coders, and will make future development and modding markedly easier. The next update (0.9) will be fairly art intensive.
That said, as someone in the thread mentioned earlier, the art requirements for the game alone are nearly 5K/month and most of the development costs are funded personally by Ron and a small handful of supporters. Ron doesn't spend much time fundraising or soliciting financial support, but he brought it to public attention recently that roughly 4500 of the Patreon followers don't contribute anything at all. If even a portion of them did, it'd make a huge impact.
If you want new chapters and new characters sooner, please do consider heading over to the game's Patreon and signing up. Even paying a buck a month will shave months off of the development timeline if enough people do it.