The latest patch that added content is from March this year. The next content patch is ostensibly going to enter public testing in the coming weeks (before the end of the year). Depending on how that goes it might release as soon as this year. This is their biggest content patch yet which adds a new biome to the game.

Its not the fastest working dev team out there but the answer is yes, the game is still receiving content updates. After the Mistlands biome there's still two more to add until the game is finished. Expect that to take a couple of years.