Patch 1.31 is required before installing 1.40 or 1.50. You do not need it if you have Steam or GoG version, they already come with 1.40 installed and need no update. If you’ve got the game from other sources and have versions 1.1 or 1.2 then the update to 1.31 is required.
Determine Version
The easiest way to determine version is to run the game and check bottom right corner of the Title screen:
Here we see version 1.50.18. If you’re unable to run the game, consider the following:
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Steam and GoG releases always have version 1.40 (
Ver 1.40b23), no need for 1.31. -
The original CD most likely contains version 1.1 or 1.2, update to 1.31 needed.
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You can infer version from the ORION2.EXE file size. As a rule of thumb if its 2612009 bytes or less then it has version 1.2 or 1.1. The latest 1.40 always has 2644842 bytes. Version 1.31 varies between 2612010 and 2617457 bytes. Version 1.2 is smaller at 2598945 bytes, and 1.1 is even smaller.
Install 1.31
Unzip the package into the game directory overwriting existing files. The game directory is the one where ORION2.EXE file is located.