Downloaded OpenLP 3.1 and installed after using 3.1.0rc4. Had warning about replacing a newer version. Continued anyway. My Openlp 3.1 rc4 data was moved to a directory. I was able to restore the data.
Make a back-up before install! (which always good advice)
Version 3.1.0 checks the INI file and finds 3.1.0rc4 and then assumes it is installing on a newer version.
When installing 3.1.0 after using 3.1.0rc4 change the version in the data/OpenLP.ini as shown below, BEFORE running the version 3.1.0 and it works fine.
Fred