14 DAY TRIAL // Canonical has just upgraded the Firefox packages in Ubuntu 15.04, Ubuntu 14.04 LTS, and Ubuntu 12.04 LTS operating systems after a regression has been identified. From the looks of it, the default search engine was set to Yahoo.
Regressions happen all the time, and they are often caught by developers in time. Having the default search engine modified by the upgrade is not a big problem, but it's enough to make devs and maintainers release a new version of the web browsers. A reader pointed out the upgrade that landed in the repos and we have a little bit more information about the problem than what is mentioned in the security notice.
The developers did say that after the upgrade process was completed, some users in the US reported that their default search engine switched to Yahoo. Apparently, this problem only affected some Ubuntu users and not everyone. The good news is that everyone who is using Ubuntu will be receiving this update and the same goes for all the distros that have Ubuntu as a base.
This is still Firefox 40
The version number of Firefox hasn't changed, so don't expect to find something else. This release is only here to correct a problem that was introduced with the previous update.
The details on Launchpad regarding this update are a little bit more descriptive: "Disable geo-specific search defaults, and clean up profiles that have been inadvertently switched to the wrong search default."
Also, the description of the bug sheds more light. "When Mozilla initially switched to Yahoo by default for US users, it did this with a non-localized geo-specific preference (browser.search.defaultenginename.US), used when the locale was en-US, the user was in a US timezone and Firefox was not a partner build. This meant that Ubuntu builds continued with Google as the default search engine. Some users are reporting that the default is switching to Yahoo after upgrading to 40.0, which is not intentional."
To get this new version, you only have to upgrade your system.