IPython will always be 100% open source software, free for all to use and released under the liberal terms of the modified BSD license. But while the whole team does its best to work efficiently, and we actively try to find funding from multiple sources, the reality is that we have limited resources and this fact hinders our development capabilities.
If you have found IPython to be useful in your work, research or company, please consider making a donation to the project commensurate with your resources. Any amount helps!