Open alpha testing of the 5.0 HD mod (online lobby).

I don't quite understand what needs to be done, what to compare with what, and how it should be done correctly?

You need to check where the folders with the plugins that work correctly are located and what is inside these folders. Compare the location and contents of the folder with the non-working plugin with the folders of the working ones. For example, here is the location and contents of the folder with version 1.38: http://prntscr.com/ilwhaq
If I remember correctly, I had problems when the plugin itself (the .dll file) was in this folder, and there was also another folder called HW_rules_1.38, and the plugin was inside it. Accordingly, I took the .dll out of this extra subfolder, and everything started working.