Start jEdit and go to the menu “plugins->plugin-manager” and click on “download options” and choose a “mirror” near you and hit OK. Click on the tab “update”.If Lazy8Ledger shows up in the list then you can choose “Lazy8Ledger” and hit the “install all” buton. But normally this list will be empty which means everything is already updated.

Please consider providing this page in English also. Thanks.
-Thomas
Oops. Now it’s fixed…