After 3 release candidates, the final release version for Dolibarr 3.1 is available. This version is called 3.1.0.
There is absolutely no new features compared to 3.1RC1, 3.1RC2 or 3.1RC3 but contains fixes to work on old PHP version (< 5.0) and fixes on discount lines for invoices. Other minor fixes are also included. If you already use 3.1 release candidate, upgrade only if you experience problems.