Well, I investigated the version available with a 4g ipod that I use for testing and it gets the latest version from the app store.
I believe you do have the latest version of the app. I think the 1.9 you are referring to is the size of that distribution in MB rather than the actual version number.
However, there are differences in how the app operates with 7.1 versus 6.1 iOS based on the music player engine that is available from the operating system. I also have not put nearly as much testing time into the 6.1 compatible music engine since the remaining distribution of that iOS version is very small. Your description of when the freeze occurs does give me a sequence to test so I will do some tests and see if I can figure out what is happening.
In the meantime, if you had a device that runs 7.1 iOS, that would probably avoid the problem for you.