This message was posted on behalf of Intel Corporation
Thanks for reaching out.
I'll try my best to answer your questions, so I hope you find the following information helpful:
You can find the latest source package here: http://iotdk.intel.com/src/3.5/edison/, it has the version 1.7.3. That .zip file includes a README with the steps to build the image.
About the newer releases, we don't have plans for it yet. So I can't answer this question for