Teachers, Admins and Staff may face an issue that the orange upgrade button is not displayed when trying to convert their user site to SLS2.
The button to upgrade user site to SLS2 is missing when the school site is not published.
School Site Not Published
School Site Published
You can check if the school site is published by opening the site URL; if the login page is displayed right away, it means that the site is not published:
Reach out to a School Webmaster and ask them to publish the School Site so that you could update your user site and edit it.
Once the school site is published, the Try An Upgrade Button should be visible once you access your user website. You should be able to convert it to SLS2.