Flarum Forum Server not found

luceos How do i install it on windows?
i tried to install normal flarum and then update composer but i get

PHP Fatal error:  Uncaught Error: Class 'Flarum\\Forum\\Server' not found in www\\flarum\\index.php:14

You seem to have missed to run composer install or something.

Please don't hijack another discussion.

@luceos i wanted to ask how to install the dev flarum version?

Then you most likely just copied over the composer.json, without in fact re-installing flarum/flarum with dev-master?