+## 4.1.0 -> master
+
+### New indexes for reverse lookup
+
+The reverse lookup algorithm has changed slightly to improve performance.
+This change needs a different index in the database. The required index
+will be automatically build during migration. Until the new index is available
+performance of the /reverse endpoint is significantly reduced. You should
+therefore either remove traffic from the machine before attempting a
+version update or create the index manually **before** starting the update
+using the following SQL:
+
+```
+CREATE INDEX IF NOT EXISTS idx_placex_geometry_reverse_lookupPlaceNode
+ ON placex USING gist (ST_Buffer(geometry, reverse_place_diameter(rank_search)))
+ WHERE rank_address between 4 and 25 AND type != 'postcode'
+ AND name is not null AND linked_place_id is null AND osm_type = 'N';
+```
+
+## 4.0.0 -> 4.1.0
+
+### ICU tokenizer is the new default
+
+Nominatim now installs the [ICU tokenizer](../customize/Tokenizers.md#icu-tokenizer)
+by default. This only has an effect on newly installed databases. When
+updating older databases, it keeps its installed tokenizer. If you still
+run with the legacy tokenizer, make sure to compile Nominatim with the
+PostgreSQL module, see [Installation](Installation.md#building-nominatim).
+
+### geocodejson output changed
+
+The `type` field of the geocodejson output has changed. It now contains
+the address class of the object instead of the value of the OSM tag. If
+your client has used the `type` field, switch them to read `osm_value`
+instead.
+
+## 3.7.0 -> 4.0.0
+
+### NOMINATIM_PHRASE_CONFIG removed
+
+Custom blacklist configurations for special phrases now need to be handed
+with the `--config` parameter to `nominatim special-phrases`. Alternatively
+you can put your custom configuration in the project directory in a file
+named `phrase-settings.json`.
+
+Version 3.8 also removes the automatic converter for the php format of
+the configuration in older versions. If you are updating from Nominatim < 3.7
+and still work with a custom `phrase-settings.php`, you need to manually
+convert it into a json format.
+
+### PHP utils removed
+
+The old PHP utils have now been removed completely. You need to switch to
+the appropriate functions of the nominatim command line tool. See
+[Introducing `nominatim` command line tool](#introducing-nominatim-command-line-tool)
+below.
+
+## 3.6.0 -> 3.7.0
+
+### New format and name of configuration file
+
+The configuration for an import is now saved in a `.env` file in the project
+directory. This file follows the dotenv format. For more information, see
+the [installation chapter](Import.md#configuration-setup-in-env).
+
+To migrate to the new system, create a new project directory, add the `.env`
+file and port your custom configuration from `settings/local.php`. Most
+settings are named similar and only have received a `NOMINATIM_` prefix.
+Use the default settings in `settings/env.defaults` as a reference.
+
+### New location for data files
+
+External data files for Wikipedia importance, postcodes etc. are no longer
+expected to reside in the source tree by default. Instead they will be searched
+in the project directory. If you have an automated setup script you must
+either adapt the download location or explicitly set the location of the
+files to the old place in your `.env`.
+
+### Introducing `nominatim` command line tool
+
+The various php utilities have been replaced with a single `nominatim`
+command line tool. Make sure to adapt any scripts. There is no direct 1:1
+matching between the old utilities and the commands of nominatim CLI. The
+following list gives you a list of nominatim sub-commands that contain
+functionality of each script:
+
+* ./utils/setup.php: `import`, `freeze`, `refresh`
+* ./utils/update.php: `replication`, `add-data`, `index`, `refresh`
+* ./utils/specialphrases.php: `special-phrases`
+* ./utils/check_import_finished.php: `admin`
+* ./utils/warm.php: `admin`
+* ./utils/export.php: `export`
+
+Try `nominatim <command> --help` for more information about each subcommand.
+
+`./utils/query.php` no longer exists in its old form. `nominatim search`
+provides a replacement but returns different output.