There has been a pronouncement from the all-powerful ones at Wizards of the Coast:
Magic: The Gathering Tournament Rules Change: Extended
On July 1, 2010, the following sets will leave the Extended format: Ninth Edition, Mirrodin, Darksteel, Fifth Dawn, Champions of Kamigawa, Betrayers of Kamigawa, Saviors of Kamigawa, Ravnica: City of Guilds, Guildpact, Dissension, and Coldsnap. From that point forward, the Extended format will include approximately four years of Magic sets instead of seven.At that time, the following sets will be legal in the Extended format: Time Spiral, Planar Chaos, Future Sight, Tenth Edition, Lorwyn, Morningtide, Shadowmoor, Eventide, Shards of Alara, Conflux, Alara Reborn, Zendikar, Worldwake, Rise of the Eldrazi, and Magic 2010.
With the upcoming release of Scars of Mirrodin, the following sets will leave the Extended format: Tenth Edition, Time Spiral, Planar Chaos, and Future Sight. One year’s worth of releases will leave Extended with the release of every subsequent fall Magic set.
