I know you posted the link to the solution on the end-user side, but just incase you are having trouble yourself:
All you need to do is, disable 'Enable strict checking of objc_msgSend calls' in the target settings.
http://www.shilocity.com/snaps/Screen%20Shot%202015-03-26%20at%207.57.12%20AM.png
Other then that, it would be nice to have a direct Sparrow fix, but I don't see it being too necessary, in my opinion. It's not a deprecated call, it just requires strict casting of the function, if the strict checking is enabled.