User manual, guide, instructions

Is there any kind of user manual other than the one written in 2014? User Manual

eM Client has many features, and about half of them require trial-and-error procedures to figure out how to use them. I’d trade half of the nonessential features for a good manual.

The documentation linked from the help in version 8 refers to version 7.1 (2018):
https://www.emclient.com/webdocumentation/en/7.1/eMClient/Default.htm