ConcernedApe is working away on his next game, but Stardew Valley is still receiving patches. Version 1.5.5 was released today, and while it adds no new content it makes "some important technical changes for modders, some quality of life changes, and some bug fixes" for the farming simulator.
The big change for modders is that this patch migrates the game from XNA to MonoGame. Both are frameworks for making games, but XNA hasn't been developed by Microsoft since 2013, and so the shift "futureproofs the game" in the words of the full patch notes. It also allows mods to access more than 4GB of RAM.
Bug fixes aside, quality of life fixes make up the bulk of the rest of the patch. Starting a new game will default to whatever settings you used last time, you can now buy back items you accidentally sold, and you can nudge pets out the way by clicking on them while you're building stuff.
There are more modding improvements on the way, as the patch notes also say that they're working with the creator of SMAPI, a popular mod loader for Stardew Valley, to introduce some "long requested 'holy grail' changes" to make modding easier.
ConcernedApe - aka Eric Barone - announced last month that his next game would be Haunted Chocolatier, about running a chocolate shop staffed by ghosts. I'd never have thought of it, but in retrospect it sounds like the perfect followup. There's no release date as yet, although Barone has shared more about how its combat will work.