How to install Tor Browser 4.5a3 on Ubuntu/Linux Mint via PPA

Tor Browser 4.5a3 is based on Firefox ESR 31.4.0, which features important security updates to Firefox. Its updater now contains the code for verifying signed update files and does not accept unsigned ones anymore. Moreover, this release includes an updated Tor, 0.2.6.2-alpha, an updated meek, 0.15, which is now working again, and a bunch of additional improvements and bugfixes.

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

Here is the changelog since 4.5-alpha-2:

All Platforms
- Update Firefox to 31.4.0esr
- Update Tor to 0.2.6.2-alpha
- Update NoScript to 2.6.9.10
- Update HTTPS Everywhere to 5.0developement.2
- Update meek to 0.15
- Update Torbutton to 1.8.1.3
  - Bug 13998: Handle changes in NoScript 2.6.9.8+
  - Bug 14100: Option to hide NetworkSettings menuitem
  - Bug 13079: Option to skip control port verification
  - Bug 13835: Option to change default Tor Browser homepage
  - Bug 11449: Fix new identity error if NoScript is not enabled
  - Bug 13881: Localize strings for tor circuit display
  - Bug 9387: Incorporate user feedback
  - Bug 13671: Fixup for circuit display if bridges are used
  - Translation updates
- Update Tor Launcher 0.2.7.1
  - Bug 14122: Hide logo if TOR_HIDE_BROWSER_LOGO set
  - Translation updates
- Bug 13379: Sign our MAR files
- Bug 13788: Fix broken meek in 4.5-alpha series
- Bug 13439: No canvas prompt for content callers