Wikipedia to the rescue...
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In May 2008, Jackson stated that he was working with Warner Bros. on releasing the trilogy in high-definition Blu-ray format, although no release date had been confirmed at that time.
On April 16, 2009, Warner Bros. announced that it would be releasing the theatrical versions of the trilogy on Blu-ray in a boxed set later in 2009. Jackson also said that the Extended Editions were in development for Blu-ray and would be released in conjunction with the theatrical release of The Hobbit in 2011.
In July 2009, Jackson announced in an interview that the Extended Editions will be released sometime in 2010 on Blu-ray with possibly new special features to be made.
The three theatrical versions of the films were released on Blu-ray disc on April 6, 2010. The press release stated that the extended editions will be released "at a later date". Alongside the Blu-Ray announcement, it was announced that the three films would become available for digital purchase for the first time on all major digital service providers.
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