The first alpha release of the 4.5 series is available from the extended downloads page and also from our distribution directory.

This release features a circuit status reporting UI (visible on the green Tor onion button menu), as well as isolation for circuit use. All content elements for a website will use a single circuit, and different websites should use different circuits, even when viewed at the same time. The Security Slider is also present in this release, and can be configured from the green Tor onion's Preferences menu, under the Privacy and Security settings tab. It also features HTTPS certificate pinning for selected sites (including our updater), which was backported from Firefox 32.

This release also features a rewrite of the obfs3 pluggable transport, and the introduction of the new obfs4 transport. Please test these transports and report any issues!

Note to Mac users: As part of our planned end-of-life for supporting 32 bit Macs, the Mac edition of this release is 64 bit only, which also means that the updater will not work for Mac users on the alpha series release channel for this release. Once you transition to this 64 bit release, the updater should function correctly after that.

Here is the complete changelog since 4.0.1:

More:

Tor Browser 4.5-alpha-1 is released | The Tor Blog