Windows: See the Windows page.
Here is a short document about building and installing.
WindowsSee the Windows page.
Install from the PPA:
The upplay packages for the i386, amd64 and armhf (Raspberry Pi) architectures are hosted in the upmpdcli repository.
See here for how to add the repository to your system.
Then use the following to install upplay:
Fedora 25 RPMs here.
Fedora 26 RPMs here. Also works for Fedora 27 and 28.
Fedora 29 RPMs here. Fedora 29 libupnp 1.8 is now properly updated and not crashing any more, so you can use the system libupnp instead of the 1.6 which was previously supplied here, and upplay has been updated to use 1.8. To upgrade from a previous version, you will probably need to remove the 1.6 libupnp and libupnp-devel packages, then install the system's libupnp-devel, and the libupnpp and upplay packages from the above link.
Dependancies: libupnp-devel libcurl-devel qt5-qtscript qt5-qtwebkit
See the Windows page here..
NOTE: If upplay mostly works but its state does not update (e.g. no time progress), you probably need to allow incoming connections through the Windows Firewall (UPnP state update events need HTTP connections from the player to the control point).
A number of kind people are producing packages for other systems: