Yesterday the version was released macOS High Sierra public beta 3 for all users who are subscribed to Apple's public beta program. In this sense, the public beta versions are always one step behind the beta versions for developers in terms of number, but in principle they add the same novelties in both versions.
Last Monday the version was sent beta 4 for developers and since yesterday afternoon many of the users who have the public version of the operating system installed. In this new version the changes are directly focused on the functionality, bug fixes and system stability.
Apple has until last August to improve the version of macOS High Sierra and test the added improvements, then it is supposed to be released for all users and the fixes will be minor. In any case, it is a version that does not add too many aesthetic or functional changes visible to the user, but if you add numerous changes to the system itself such as the news in Safari, the way to store files and display videos in HEVC format, among other improvements.
It is always good to remember that it is a new beta version and you have to take it as such, so installing this public version is good to be among the first to try the new features but it is better to do it on an external disk, partition or Mac than not be the main. In this way, what we will avoid is that the failures that this beta could have become a problem of use and have a bad experience for it. If you want to access the beta for the first time you can do it from this link and if you already had the public beta 2 installed on your Mac, you will find the update in the Mac App Store> Updates.