From Firefly Studios:
Stronghold Crusader HD Patch upgrades Stronghold Crusader to the new HD version. This patch will make multiple new resolutions available depending on your configuration.
This patch also fixes the Skirmish Masters file. Unfortunately old skmasters.dat files from v1.0 and v1.1 no longer work with Stronghold Crusader HD.
Windows 8 - Stronghold Crusader 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 allows the patch to be installed even if it cannot automatically detect the game.