This is a summary of the changes available in Dart 1.5.
New MapMixin, SetMixin, SetBase
HttpClient - new maxConnectionsPerHost property
“Dartium” is now based on Chrome 36
Better version resolution
Support for lazy transformers
Remove support for the deprecated "asset" directory
Optimize startup for pub build and serve
Improve performance and memory usage of pub serve on Windows
New mobile support - launch and debug on a connected Android device
Integration with Observatory
Reduced memory usage
New low memory warnings and recommendations
Various refactoring, debugging, and editing fixes
Better allocation profile page with faster refresh.
Better code coverage UI and faster code coverage collection.
Improved VM and Isolate landing pages.
It’s now possible to identify hot DOM calls using the CPU profiler.
Debian wheezy binary package
Get the Dart SDK on a Debian server
Find it on the download page for Linux