Vladimir Lomov <lomov.vl@yandex.ru> wrote:
> ** Dmitry Alexandrov <dag@gnui.org> [2020-06-06 15:36:06 +0300]:
>> Vladimir Lomov <lomov.vl@yandex.ru> wrote:
>
>>> I tried to use '-F' option of 'emacsclient' but I didn't get desire result, WM_CLASS isn't changed, only WM_ICON_NAME.
>
>> Works for me (Emacs 28, no toolkit).
>
> Do you able to change WM_CLASS?

Yes.

> 3. Run emacsclient (the socket is created by systemd, emacs started by service)

That is with all your customizations.  Try to reproduce it with

	$ emacs --quick --fg-daemon=test-wm-class