I am trying to update an old site that still uses Ubuntu Trusty. When I go to Deploy Settings, I do not see the section that lets me select the build image on my other sites.
I see this section on my other sites that need updating. This particular one differs by using manual deploys.
I tried setting an environment variable _system_version with the value 20.04 but got an error message - variable names must start with a letter.
Any suggestions about what to try next?