Sysimage file extension

From Creating a sysimage · PackageCompiler (
“We start Julia with the flag to load the new custom sysimage (or sys.dylib , sys.dll on macOS and Windows respecitively)”

I have successfully used the .so file extension on my windows computer, but I changed it to .dll based on this documentation. But If .so works on windows, where does it not work? Is the an advantage to using .dll? If I want to keep it as general as possible, should I use .so, becasue it works on Windows (my experience) and Linux (based on the quote from the docs)?

The file extension doesn’t matter at all, it’s just that so/dylib/dll are the default extensions on Linux/MacOS/Windows.