We will allow Apache 2 license dependencies into Stan Math which is itself new BSD license. This impacts GPL2 licensed projects.
This is a trip wire consensus decision. Any reasonable objection shared in this thread by midnight September 14th anywhere on the planet will ‘trip’ a review, otherwise the proposal will be adopted. Description of the experimental trip wire process is at the post designated by: Licenses of dependencies
Extensive discussion of the proposal at the thread: Licenses of dependencies