I have found the answer in another question, which I couldn't reach before:
How do I get rid of the "Release 1" in the Page Header of the Sphinx Latex Output?
ddbecik has answered the question with following code:
release = ''
latex_elements = { 'releasename': '' }
So, for saying it literally, I was supposed to put empty string into release
variable and to add releasename
directive in the latex_elements
section, also containing empty string.
It works like a charm, therefore I am sorry for doubling question and I hope it will be easier for other to find answer in future.