Updating ubuntu 7 04
Comprehensive backups and extensive testing are strongly advised. Although many systems can be upgraded in place without incident, it is often safer and more predictable to migrate to a major new release by installing the distribution from scratch, configuring services with careful testing along the way, and migrating application or user data as a separate step.
You should never upgrade a production system without first testing all of your deployed software and services against the upgrade in a staging environment.
They both have a DEB (for the package system) and a ZIP distribution.
This answer summarizes the recommended community upgrade process.
You should always read the release notes for any potential issues that may affect your upgrade.