play on either platform, until June 26, 2014, when Version 3 was shuttered. On July 16, 2014 version 4 became the sole client for Magic: the Gathering Online. Card sets available As of March 2014 with the release of Vintage Masters, almost all Cards that are tournament legal for at least one supported format are available. Most of the remaining tournament legal cards that are not printed are basically considered as tournament unworthy (such as cards that only trigger their ability during drafts). The earliest set available upon release was Invasion, which had been released in printed form in October 2000; all sets moving forward were made available online as well, with the exception of some self-parody expansions (Un-sets) and multiplayer sets (like Conspiracy). For the first 10 years of "Magic Online" sets released online three or four weeks after they released in paper in an effort to appease "brick & mortar" retailers. However, a policy of shortening this delay (to about two weeks) was instituted to allow professional players (who often use "Magic Online" for testing) to prepare for Pro Tour events (which usually happen two weeks after the release of a new set) and to "increase cohesion" between paper and online Magic. Wizards of the Coast has since released more pre-Invasion cards online. In autumn of 2005, Mirage was released online, nine years after its 1996 print release. This set was chosen as the earliest set usable on Magic Online because it was the first to be designed with both Limited and Constructed play in mind and the first to be intended as part of a three-set block. Additionally, Wizards unambiguously owns the rights to the artwork in Mirage block, and Mirage block contains no ante cards (unlike Ice Age and Homelands). It has been confirmed that the eventual goal of the developers was to have every expansion set from Mirage onward available online. For cards released before Mirage, special MTGO-exclusive compilation sets called Masters Editions were created. These sets range in size from 195 to 269 cards. Most of the cards in a given set were previously unavailable on Magic Online. Exceptions are usually made to create enjoyable Masters Edition limited environments or to make specifically illustrated cards available online. The first Masters Edition was released on September 10, 2007, with Masters Edition II following in 2008, Masters Edition III in 2009, and Masters Edition IV in