Glen Products were running two different stores (Restrooms and MyEasyParts) in a single magento installation. We had to upgrade the Magento installation from 1.8 to 1.9, while keeping all the functionality of 3rd party extensions working. Also, managing the downtime and keeping it to minimum was one of the top priorities of our client.
We upgraded the installation using Magento's best practices on our demo server and removed all the conflicts. Once everything worked, we took the changes to the live server and deployed the whole latest version within the set downtime.
Achieved a smooth upgrade without any problems and with a minimal downtime.