The team at BitTorrent Labs has released a new Sync beta build that incorporates all of the planned Sync Pro features and allows users to update from the stable Sync 1.4 build while importing all of their folders. The latest build, version 2.0.51, is available for Windows, Mac, and Linux PCs as well as Android (Sync 2.0.34) and Kindle Fire mobile devices. Users can grab the download from this Sync forum thread.
Sync 2.0.51 was deployed to test the upgrade and folder import path from 1.4. Unfortunately, the new build is not compatible with any previous Sync 2.0 (alpha) builds so users that are already testing will have to start from scratch whereas if you are just now jumping in as a tester you can keep your folders set up as is.
The latest Sync beta turns on all of the Sync Pro features (image from Sync blog).
I was able to successfully update to the new build on my main PC and Android smartphone. Unfortunately, I can not go into many details regarding my experience as testers have been asked to not talk publicly about the builds until further along in development. You are welcome to try it out for yourself though.
Sync 1.4 (left) users can upgrade to the new Sync 2.0.51 beta (right) and import their folders.
The public forum thread does mention that the new build includes a trial of Sync Pro features including a private identity that allows you to easily link all of your devices together and a selective syncronization feature that uses placeholder files and allows you to choose which files you want to download for offline access on a per device basis (a feature that caused controversy for Microsoft over OneDrive removing placeholder files in Windows 10). A new permissions engine is also in effect and you are able to change permissions after the fact now without generating a new link.
In all, Sync is still in development and they have some neat features in the works that will make it more competitive with other file syncing services.