Valve have remembered that Dota Underlords exists and needs some attention, with an announcement that it's going to see a hero rotation soon.
Addressing the fact that since release, updates have slowed down and have mostly been balance changes, they mentioned how their team has been helping "other recent Valve projects ship" and external issues "2020 everybody" (COVID19 interrupted everything). They've mentioned that in the "next few weeks" we will get a hero rotation bringing in 8 new heroes, along with new alliances, new items and a rank reset. Hopefully this is the start of more updates to come.
They also showed off a preview of two heroes coming:
While it's nowhere near as popular as other games, the Dota Underlords playerbase seems to have evened out. Dropping from an all-time peak of 202,334 after the full release down to around 6-7 thousand now. It's obviously a drastic drop but as a Valve game, excitement and interest would have obviously been inflated. Looking at the Steam charts for it, it seems to have stabilised to where it is now back in mid-July. It's good that Valve support their games for a long time but with such a low playbase comparatively with their other titles, will they keep going with it? Will be interesting to see.
You can play Dota Underlords free on Steam.