This version brings the last major breaking changes to AvalancheJS before mainnet, and there are a lot of breaks from the previous version. More importantly, there's a lot of features added. This version is very close to being feature complete with AvalancheGo, minus a few features to be added in future minor patches.
This release enables validation and delegation transactions to be built and signed locally to be sent to any node to begin a validation or delegation of stake. It cleans up many class naming schemes and methods to be more consistent. It adds new apis such as platform.getMinStake and platform.getHeight. There has also been some validation added to some key points in the code.