I recently updated to MAC OS 11.4 and now my LibreOffice version 5.0.2.2 won’t open.
Hello,
any new release is known to work (either 7.1.4 or 7.0.6) - see LibreOffice System Requirements - Apple macOS (Mac OS X)
I’d suggest to install 7.1.4, since this will be the “still” version soon (version 7.2 is on the go).
Remark
Be aware that you might be required to provide Full Disk Access to LibreOffice.app, due to (new !?) restrictive security settings of macOS related to non-apple-ecosystem-applications. Follow instructions according to question Unable to Save or Save As any document even in Safe Mode to prvide Full Disk Access.
Hope that helps.