Version 1.7.3 is designed specifically for Skyrim 1.9.32.
For many, the reason to stay on a specific non-Steam version of 1.9 is modding. If you are running 1.9.32, you use the classic version of the Skyrim Script Extender (SKSE) . skyrim+update+19+download+non+steam+exclusive
Vital memory management fixes required for heavy modding. Downloading the Update for Non-Steam Versions Version 1