I downloaded the LMMS 1.2 RC6 AppImage and I flagged it as an executable using chmod. When I went to run it, nothing happened, so I opened up a terminal window and ran ./lmms.AppImage (to see if I got an error message). It returned this:
I'm running Fedora 28 with Cinnamon and have QT5 installed.bash: ./lmms-1.2.0-rc6-linux-x86_64.AppImage: cannot execute binary file: Exec format error