Just noticed the same thing. I own the game here on GOG, not on Steam, so it was pure chance I saw it appear on the "recently updated" section.
It's quite a major update, by the look of it: getting rid of DOSbox and moving the game to ScummVM.
N.B, Buried at the end of the list of fixes, after a load of spoilers, it says that the update breaks your saves. Saves from the DOSbox version won't work with the updated ScummVM version. Therefore, people who are currently deep into the game - and Good-Old-Game purists - might wish to archive their current installers in case GOG does update the game!
Here's the full update description, from Steam, dated February 26th 2014: SPOILERS
An update is out now for IHNMAIMS which includes the following changes:
Engine Change for Windows, Linux and Mac OS X - DOSBox has been replaced with ScummVM 1.6.0. This also comes with the following bugfixes (spoilers ahead):
When loading a save game, the music played is still the music which was playing in the previous scene before the save game is loaded
When picking up or using objects in a scene, sometimes a "ghost" object is created in the top left corner of the screen
Chapter 1 (Gorrister): After reading the note in the starting room, the hotspot for the note moves to the upper-left corner, so you can read it again and again
Chapter 1 (Gorrister): Gorrister's heart is not supposed to have a "use" phrase attached to it (it's not used anywhere, it's only given), but when "used", an incorrect reply is given to the player ("It's too narrow for me to pass", said when Gorrister tries to pick up the heart without a rope)
Chapter 1 (Gorrister): Using the knife to cut out Edna's heart can lead to unexpected behavior the second time this is performed. The player is either able to talk again to the dead Edna, or get her heart again and be stuck
Chapter 1 (Gorrister): the left graffitti in the restroom can't be examined. Gorrister just walks back to the bar instead
Chapter 1 (Gorrister): When Edna drops her key in the freezer room, the user can hover over 2 items with the cursor ("The key" and "Edna's key")
Chapter 3 (Benny): After talking to the child via the monitor, Benny walks backwards
Chapter 3 (Benny): Putting the lottery bag into the hole and retrieving it back from there summons another Psychic Profile book in the inventory (instead of the bag icon)
This engine change unfortunately means that any saved games made previously will no longer work with this new update.