The library depends on gson version 2.5:

[nirfeldman]

You should consider testing it with more versions - maybe 2 versions (so apps that use a different version of gson). For us it's not an issue.
Your pom should specify which versions are acceptable.
e.g.:
[2.4,2.5]

This is low priority from our end (since it does not collides) but might be an issue for an app that is using gson on different version then 2.5

[JiamingFB]

right now the sdk pom requires gson 2.5+, and default to 2.5 unless it has conflict with other dependencies.