Publishing and Versions
Changes made to a container do not take effect on a site or mobile app until you publish the container. Once you've added or edited tags, triggers, and variables in a container, you'll need to publish the container in order to make your additions and changes live on the site/app.
To publish a container, click on the publish button at the top right hand side of the screen.
A version is essentially a snapshot of a container. You can save the current state of a container as a version at any time. This allows you to save and preserve your work and go back to a previous version if you need to.
Saving a version is independent of publishing. You can save versions at any time and you never need to publish a version unless you want to. However, you cannot publish a container without first saving it as a version. As a result, you'll have a saved version of anything that has been previously published. This can make it easier to recover from mistakes. For example, if someone accidentally publishes a container version before it's ready for production, you can simply publish another version that has been debugged and is known to work.
To save the current state of the container as a version, click the container publish menu (next to the Publish button) and then click Create Version.
To publish a previously saved version of a container to the site, click on Versions in the top navigation. Click the desired version in the table, then click Action → Publish. Google Tag Manager maintains a publish history, so you can see when versions were live and who published them. To see the publish history, go to Versions and look for entries with a date in the Published column.
To replace the current container version with a previously saved version, go to Versions. Click on the Action link next to the desired container version and click the "Edit as new version" link in the Action drop-down list. This replaces the current container draft with the content of the container version you've selected. This action does not change the published container version.