if you are currently using any older version of SMF (including SMF 1.x, SMF 2.0.x, or one of the SMF 2.1 Betas or RCs), you can upgrade directly to 2.1.4 from whichever version you are currently using by using the "Large Upgrade" package from the Download page. Be aware that using this upgrade method will require you to reinstall any customizations that you have added to your forum, so if you are running SMF 2.1.0 or higher, it is recommended that you apply the successive patches instead of using the Large Upgrade.