The company promised last week that it would release new kernel updates on Monday, January 15, 2018, for all supported Ubuntu releases. But it didn’t happen as they needed more time to thoroughly test and prepare the patches that would presumably address variant 1 and 2 of the Spectre exploit, which is harder to fix than Meltdown, so that it won’t cause any issues. Ubuntu users interesting of patching their systems against both variants of the Spectre security vulnerability ahead of anyone else, are invited to enable the pre-released updates (ubuntu-proposed) repositories in the “Developer Options” tab of the Software & Updates utility. Then simply update their installation, reboot, test if everything works, and provide feedback to Canonical.