• Caffe2 from Facebook is one of the key mobile machine learning frameworks that was not discussed in this book. More details can be obtained from https://caffe2.ai/.
• Caffe2 is a deep learning framework that provides an easy and straightforward way to experiment with deep learning and leverage community contributions of new models and algorithms.
• The original Caffe framework was useful for large-scale product use cases, especially with its unparalleled performance and well-tested C++ code base. 
• Caffe2 is an improvement over the original Caffe framework in a number of features.
• It has got a steep learning curve to understand and to start coding examples using the framework.