Yes, GPL: https://github.com/project-iris/iris/blob/master/LICENSE.md

GPL seems like a sad choice for something that would need mobile apps, there have been problems with the App Store and GPL before for example.

Since Iris was/is my PhD work, and is currently not funded, I decided to release it under GPL to retain some control over what people end up doing with it (by no means do I want to prevent adoption, hence the dual licensing escape clause).

Nonetheless I'm open to discussing other OSS licenses such as BSD or Apache, but I think such issues are a bit further down the road :)