Thank you! The next release will be in early access sometime soon, since I'm almost done, but it's a new Grind'm scenario rather than a continuation of the main game's storylines.
I've stopped guessing at timeframes for each new release unless I am 100% certain I'll meet the dates I give. Last year in particular proved I'm really bad at guesstimating. But the next story update, which will follow the upcoming release, is already in development. I've done a fair amount of writing for it and have it fully planned out with flowcharts and such.
The last story update, which is the version you played, covered every single character's storyline, which led to it taking super long to make. The future ones will be narrowed down to a few characters in particular so the updates can hopefully be done quicker. So in the next story update you can expect the continuation of Matt and Evan's stories, with Marco and Leo as a lesser but still prominent focus. The other characters will still be present in some fashion, though!