+The Nominatim tool assumes per default that the current working directory is
+the project directory but you may explicitly state a different directory using
+the `--project-dir` parameter. The following instructions assume that you run
+all commands from the project directory.
+
+!!! tip "Migration Tip"
+
+ Nominatim used to be run directly from the build directory until version 3.6.
+ Essentially, the build directory functioned as the project directory
+ for the database installation. This setup still works and can be useful for
+ development purposes. It is not recommended anymore for production setups.
+ Create a project directory that is separate from the Nominatim software.
+
+### Configuration setup in `.env`
+
+The Nominatim server can be customized via a `.env` in the project directory.
+This is a file in [dotenv](https://github.com/theskumar/python-dotenv) format
+which looks the same as variable settings in a standard shell environment.
+You can also set the same configuration via environment variables. All
+settings have a `NOMINATIM_` prefix to avoid conflicts with other environment
+variables.