Since they only release a 32 bit version of the RPM form Fedora, I had to build the x64 bit version from source. Here are the steps I used to build it. You should be able to follow these steps even if you have no build experience. You just need to cut an past these commands into a Fedora terminal. This is a how to of for OpenTX Companion on Fedora, although it should work for OpenTX Companion on CentOS andOpenTX Companion on Redhat also.
First you need to get everything you will need to build Open TX Companion 2.1 .