Some installations might want to use TLS 1.1 or 1.2 instead of 1.0 provided by default by Openfire. So there could be an option or system property to enable the higher version (although this might don't work with Java 7).
An example of code change in the forum thread.
Note that this issue is specific to LDAP connectivity. Such a setting is available for client-to-server and server-to-server connections, as well as for components and connection managers (all configurable through the "advanced configuration..." option of the relevant "connection settings" pages in the admin console.