Released on September 10th, 2019.
There's no devlog to this update so the patch notes are lost to time.
But I compared the two builds and saw a few differences between 1.0 and 1.1
Below are the differences between the two in replacement for "Patch Notes".
1- A Bridge was added in-between the two playable rooms.
And due to the inclusion of the bridge, the two rooms were moved from each other.
2- The Pose of the Smirnov Ragdoll is different.
3- A canned drink got added as a prop.
4- Smirnov has a Hat on his head.