Paradox has announced the release date for Hearts of Iron 4 (opens in new tab): Man the Guns and it's set for release later this month on February 28.
Man the Guns (opens in new tab) will bring new depth to the naval side of the game with a host of new features for democratic powers including new alternate history paths, new research components for ship design, and governments in exile. You can check out the full list of the new features here (opens in new tab).
To coincide with the launch of the expansion, Paradox is also releasing a free major update which will include new naval aspects such as the training of pilots and sailors as well as the Fuel resource to give a more authentic experience.
Hearts of Iron 4 is a strategy game based in the World War 2 era and was initially released back in 2016. It's had a number of expansions in that time—you can see what we thought of the game in our Hearts of Iron 4 review (opens in new tab).