Once again, Telltale hasn't yet updated their blog about the new release of Law and Order: Legacies, but the penultimate episode, Episode 6: Side Effects, is now available for iPhone, iPod Touch, and iPad.
The game can be purchased from within the Law & Order: Legacies universal app, which is available from iTunes here. The game is USD$2.99 if you buy the episode individually, or USD$12.99 for the season package. Owners of the season package can play the episode (as well as episodes 1-5) immediately. Episode 7 isn't out yet, but judging from the quick release schedule of the iOS version, it will be released soon.
There is no time frame set for when episode 6 will be released for PC and Mac.