Activision have leaked the release date for Destiny: Rise of Iron as well as a bunch of information. It was up on Destinythegame.com before swiftly being taken down. Interestingly enough, it will release on September 10th but only mentions PS4 and Xbox One. It’s safe to assume that it’ll come to PS3/360, but it does seem odd they were were omitted.
Some more information about the expansion was also leaked in the below tweet.