Upward and prerender

I am trying to get a website pre-rendered via prerender.io because of SEO issues. I have https://github.com/magento/magento2-upward-connector installed and configured, but it doesn’t work after I specified correct upward path, prerender URL, token, user agent conditions etc. I just don’t see how it should work, user agents specified in admin are not added to upward, so requests are processed via default pwa resolver and not forwarded to the backend. Is there anything I should do with upward.yml, or am I missing something?