This release also features an in-browser updater, and a completely reorganized bundle directory structure to make this updater possible. This means that simply extracting a 4.0 Tor Browser over a 3.6.6 Tor Browser will not work.
- Backup your bookmarks from 3.6.6 using the bookmark manager of Firefox.
- Remove TBB 3.6.6 completely.
- Unpack TBB 4.0.
- Start TBB 4.0.
- Import you bookmarks from the backup file.
Using add-ons other then the ones provided by TBB is not recommended.