Upgrading blades (including Liberator, Transformer, Integration Adapters and any other type of blade) is the same as deploying a new component in the Deployment Framework.
Take note of the current version of Liberator. This is shown at the top of the Liberator Status page.
Download a different version of Liberator to the one you've already deployed, and follow the same steps as to deploy.
Restart the Deployment Framework. The Liberator Status page should now indicate the new version of Liberator selected.
All previously deployed kits are stored in the <DeploymentFramework>\kits\archive directory. To revert to a previous version of Liberator or an Integration Adapter, you simply need to copy the desired kit (zip file) from the archive directory into kits, then deploy this version again.