A topic from AEG's L5R CCG Rules forum, copied for Oracle of the Void from a copy of the forum saved in October 2015, so pages it didn't save are missing. Players' names are left out; the rules officials are named. Rulings are as they stood on these dates; later rulings, the rulebooks and the Rules Archive may differ.
Best to contact a particular tournament organizer. They set tournament formats and decide what is allowed.
Some cards have been printed many times. Previous printings of cards that are legal in (say) Lotus Edition play are legal in Lotus tournaments, and are played with the wording of the most recent printing.