And the following env variable: JBP_CONFIG_TOMCAT: "{ tomcat: { external_configuration_enabled: true }, external_configuration: { repository_root: \" https://repository.example.org/\" } }"

Then is there a way to tell the buildpack to pick 1.0.0 or 1.1.0 ? Is there something like specifying { version: 1.0.0 } in the env variable ?

The environment variable configuration is a “flow” style[1] YAML representation of the configuration file[2] being configured. If you review the documentation for the Tomcat configuration[3], you’ll see that there is a `external_configuration.version` property to go along with the `external_configuration.repository_root` property.

-V



[1]: http://www.yaml.org/spec/1.2/spec.html#Flow
[2]: https://github.com/cloudfoundry/java-buildpack/blob/master/config/tomcat.yml#L23
[3]: https://github.com/cloudfoundry/java-buildpack/blob/master/docs/container-tomcat.md#configuration