update link to illustrator 2017 sdk on https://www.adobe.com/devnet/illustrator/sdk.html
We are moving away from devnet to the Adobe io site. Moving forward that will the place to get all of Adobe SDK.
We also have an early access program for our plugin partners. You may join our prerelease site you will get SDK builds way before we release it on public facing pages.
Here is the link to join Illustrator prerelease http://adobe.ly/1Q3rCPI
Sarah Khan (Illustrator team) commented
Hi A J Butler,
Thanks for raising your concerns. For now you can use https://www.adobe.com/devnet/illustrator. The previous link has been expired. We will be looking into the issue.