BookWorm Heroes was released on April 18, 2013 for iPhone and IPads. The game supported facebook friends, which you could battle and fight eachother in. The game was basically a FaceBook shill. Despite it being free, it was shut down on December 1, 2014, shutting down all servers and removing it from the AppStore. The letter board was quite small compared to the other games, only being a 4x4 box. The game looked reletivly basic, and only a few videos of its gameplay exist.
Bookworm for iOS was released on March 8, 2009. The game was compact and had look similar to BookWorm Mobile, and BookWorm for Kindle. The game was remove from the appstore on December 1, 2017. It was probably removed when apple switched from a 32-bit architecture to a 64-bit architecture. There's very old videos online, including some gameplay, and a funny video of someone spelling the N-word in late 2010.
You can download BookWorm Heroes and BookWorm for iOS above, but I'm not sure how to run them.