This beer is similar to that - in that it's also a Sour IPA but with greater ABV (around 5.5%) and it will have a slightly different hop bill. As of now, Epic is just calling it "Sour IPA". Look for a beer that will likely have a lemony citrus and floral dominate nose with sour green apples, flowery bitterness and resiny citrus peel backing it up.
Last Thursday, Epic sold 98% of their Spiral Jetty growlers that day. I would expect that the rare nature of this beer and it's sour components will make this one a hot commodity. So don't procrastinate.
And don't forget to exchange your old growlers!
Look for 50 Caliber IPA in cans in the coming weeks.