I would like to create topic which starts with lowercase.
kind of strange request, especially as a new user 
but everything has to be mentioned some day
this topic for the forum software Discourse looks fitting
https://meta.discourse.org/t/really-minor-capitalisation-of-category-names-intentional/18803
but maybe only categories, not topics, and even in that official forum every current topic starts with capital letter,
nothing to do about it, my guess,
in german less noticeable
I think it’s reasonable to have this objection as new user (immediately after I notice it), and not after years of creating topics when it would not disturb me 
However, I’m afraid I don’t understand, how is nothing to do here?
This Discourse is a forum framework on which this one is based?
If so, this was fixed there, but don’t work here?
as i said, maybe the mentioned topic was just about categories, not topics and the official forum has the same feature,
same as referred forums in
https://www.quora.com/What-are-good-examples-of-active-Discourse-org-forums
although one has a topic beginning with ‘macOS’…,
works here too, first words with capital letters are not corrected
maybe some change here if the admin ist interested and it is possible…
I have really hard time understanding you 
maybe the mentioned topic was just about categories
No. In answer you can find:
we’ve been removing the capitalization of topics
works here too, first words with capital letters are not corrected
Did you checked? If it was like that, I wouldn’t create this topic.
maybe some change here if the admin ist interested and it is possible…
And now, if there is no problem, what change do you have in mind? 
if the mentioned topic was clearly about topics, i wouldn’t habe said ‚maybe just‘…,
it looks as there is no change to topics as every topic there, like everywhere else worldwide, Discouse software of course, begins with capital letter,
‚works here‘ was about the special case ‚macOS‘…
never to forget, this is a german forum