Just wanted to inform Fedora users that haproxy-1.8.3 is now in the master branch and built for Rawhide. I will not be updating haproxy to 1.8 in current stable releases of Fedora since I received some complaints about doing major updates (eg. 1.6 to 1.7) is previous stables releases. That said, the source rpm will build on Fedora 27. If there is enough interest, I can build haproxy-1.8 in copr and provide a repository for current stable Fedora releases.
Ryan