+!!! warning
+ The default installation no longer compiles the PostgreSQL module that
+ is needed for the legacy tokenizer from older Nominatim versions. If you
+ are upgrading an older database or want to run the
+ [legacy tokenizer](../customize/Tokenizers.md#legacy-tokenizer) for
+ some other reason, you need to enable the PostgreSQL module via
+ cmake: `cmake -DBUILD_MODULE=on ../Nominatim`. To compile the module
+ you need to have the server development headers for PostgreSQL installed.
+ On Ubuntu/Debian run: `sudo apt install postgresql-server-dev-<postgresql version>`
+
+