As Ubuntu 12.04 is an LTS (long term support) release, it will be supported with security updates for a period of five years till April 2017. However, Canonical has plans to release 4 maintenance releases in this period.
But what exactly is an maintenance release?
As Ubuntu apps receive updates everyday, the installation image becomes more or less out of date to the current software. So people wishing to install a current release of Ubuntu will face major problems as they have to download a lot of updates to finish the installation.
This problem gets further magnified for LTS releases as they are supported for more years. To tackle this, maintenance releases are made that come preinstalled with updates and latest software. Thus, time and bandwidth due to updates after installation are saved.
Ubuntu 12.04 LTS will experience for maintenance releases – the first on 16th of August, another on 7th February 2013, third on mid 2013 and last on January 2014. Users wishing to install 12.04 LTS will have to install the new maintenance releases, while users who have already installed Precise and update it regularly need not worry about it.