1.2.14 has been released for Fedora 21 and newer to handle Insync not starting in Fedora 22 when using other desktop environments. The download links in the first post has been updated.
An error was also introduced in the 1.2.13 package for Fedora 21 and newer that prevents upgrading as reported by @JohnCall and @Terrence_Vergauwen. This has been resolved in 1.2.14. When upgrading from 1.2.13 to 1.2.14 please run the following commands first:
sudo dnf -y remove insync
sudo rm -r /usr/lib/insync
Upgrading from 1.2.12 and older to 1.2.14 should be ok. Apologies for the inconvenience.