How do I update my site from a UT upstream
In Pantheon's development workflow, updates to Drupal and WordPress are not applied in the traditional methods developers may be used to, such as Drush or WP-CLI, but are applied from updates in Pantheon's upstream repositories.
Likewise, updates to the UT Drupal Kit and WordPress for Texas distributions are applied via the custom upstream maintained by ITS. When new updates are available from the UT Drupal Kit or WordPress for Texas, they will be listed in your site's DEV environment, and can be applied and then pushed up to TEST and LIVE using Pantheon's normal workflow.
For more information, refer to Pantheon's documentation on applying upstream updates: https://pantheon.io/docs/upstream-updates
DO NOT attempt to update your site using Drush or WP-CLI, as you may prevent your site from receiving future updates.