From Firefly Studios:
Stronghold HD Patch This patch upgrades Stronghold to the new HD version. This patch will make multiple resolutions available depending on your configuration. The maximum resolution available could be 2560x1600. These patches will not work with the Steam versions. We're in talks with Steam about adding the HD versions and updating the Stronghold Collection versions of the games. We just need to wait for Steam to give us the green light.
Windows 8 - Stronghold now runs in Direct Draw compatibility mode on Windows 8 which means the scrolling is a bit smoother.
What's new in this version:
Version 1.3.1 solves some customers problems, allowing the patch to be installed, if it cannot auto-detect the game and fixes crash when selecting troops in the map editor and overlapping worker text bug in the information panels.