Default Grouping

I have updated to the latest version, and I do not understand the grouping of emails.
Is there any document how EmClient categories the used grouping, and can it be changed?
Kim

There is information in the eM Client online documentation.

(eM Client Documentation)

https://www.emclient.com/webdocumentation/en/9.0/emclient/default.htm

(Grouping)

https://www.emclient.com/webdocumentation/en/9.0/emclient/default.htm#E-mail/Reading%20Emails.htm?Highlight=Grouping