This release is a minor change that enhances the functionality of Node.js with Hamsters.js, version 5.6.1 introduced custom scaffolds and response handlers which allowed for things like progress bars etc. However there was a minor limitation in the way these handlers were assigned in Node.js making them impractical for continuous message handling. This is now resolved and you can now send as many messages from your workers to your main thread in Node.js as you desire.
If you would like to see an example of progress bars being updated using Hamsters.js take a look at the 1-billion-row-challenge repo.