If you not yet downloaded Dropbox 2.8 final (that comes with auto-sign in installers), go ahead and download it now or wait for the client to auto-update itself to the latest version. And today, Dropbox team has released Dropbox 2.9 series experimental build (with number 2.9.41) and is available for download with new features such as streaming sync, scrollable tray pop-up, improved initial sync performance, and over the quota splash screen.

Dropbox Streaming Sync

Dropbox team member David, on new Streaming Sync feature said " Streaming sync speeds up syncing for larger files. As a large file is uploaded to our servers, other desktop clients with access to that file will begin downloading the file in the background. This makes large files sync faster between your computers using the same Dropbox account as well as in shared folders."

Dropbox v2.9.41

For streaming sync to work, downloading system needs to using version 2.9 where uploading system can be running any.

Download Dropbox 2.9.41 testing build from here.