/2020/05/11/error-cs8107-feature-is-not-available-in-c-7-0-please-use-language-version-7-3-or-greater-in-azure-devops-build/ to https://www.wajs-dev.net/blog/2020/05/error-cs8107-feature-is-not-available-in-c-7-0-please-use-language-version-7-3-or-greater-in-azure-devops-build/