Nuget 2.7 seems to have changed how it handles packages with leading zeros in their version, for example AjaxControlToolkit (http://www.nuget.org/packages/AjaxControlToolkit
This package will install fine, but restore fails. Using fiddler to watch the request traffic, it appears that nuget is now dropping the leading zero in the version number when it is making api requests.
For example, the version listed in packages.config for AjaxControlToolkit after installing it is 7.0725, but as you can see from the attached fiddler trace, nuget is looking for 7.725, which fails.
This wasn't a problem with earlier versions of nuget.