Upgrading Gilly to a new version
You can upgrade Gilly by using plugin manager. Go to Plugins page (after you login as confluence administrator) and click on the Upgrade tab.
Click on the Upgrade Now button, and let the plugin manager download the new plugin jar automatically.
You should see a Successful message
As an alternative, you can uninstall Gilly manually from the Installed plugins page, and upload the new jar from the Upgrades tab also. The new jar for Gilly can be found on the releases page.