Since older versions of plugins may have bugs that are fixed in newer versions, you should keep your plugins updated, as a general rule. You can check to see if your plugins are up to date by visiting Mozilla's Plugin Check page, which is linked from the Add-ons Manager in current Mozilla browsers. Note: Due to a bug, the Plugin Check page may display a message that an outdated version of Java or Flash has been disabled, even though Java or Flash isn't even installed. For example, if Java is not detected, Plugin Check will display the message, Missing JAVA? For your safety, Firefox has disabled your outdated version of Java. Please upgrade to the latest version. (screenshot). The Java message will also occur if you manually disable an up-to-date Java plugin. [2] [3]