There are some breaking changes in this release, but they're for the most parts documented in the CHANGES document, and can easily be fixed by doing a search and replace through *.hl files in your existing codebase.
However, there are a lot of really cool features, such as the ability to insert snippets from collection of snippets in the evaluator, etc, etc, etc - Plus the goods are far more stable, due to multiple bug fixes, such as fixing a bug in regards to conditions ([if], [else-if] and [else]), etc.
The most important parts though, are that the system is now almost fully documented, through Markdown files, integrated also directly into the "Evaluator", in addition to that they're accessible through the project's main GitHub project page.