The trailer mainly shows off the new heroes being introduced in the new version. Tiny with his scepter upgrade also makes a appearance but what new ability he has is still unknown. At the start of the video we also caught a glimpse of Puck with a slightly altered hero model. Most probably for his scepter upgrade.
Discuss what you expect from the new version in the comments below.
Links
IceFrog's Blog - 6.68 teaser trailer