Sony has released an update that will allow Reader Digital Book owners to download content outside of the Sony store. Users of the $300 e-book device will now be able to access both free and paid content from third-party bookstores.

The move steps up the competition between Sony's Reader and Amazon's $359 e-book reading device, Kindle.

Previously, Reader owners could only shop for content through Sony's store, which has roughly 40,000 titles. Amazon has more than 140,000 titles and gives publishers and authors easy access to upload their books while the online store takes 65-percent of the profits.

Sony first introduced its Reader in September 2006. Amazon followed with its Kindle release in November 2007.