This release brings a completely new frontend for Nominatim. It has been rewritten from scratch in Python. An improved search algorithm allows more flexibility in ranking search results. The code is also more modular, so that it will be easier to customize Nominatim. The frontend is also exposed as a Python library, so that it is no longer necessary to set up a web server when using a local installation. The Python frontend is currently still marked as experimental given that this is very new code. It is still very stable and already used in production on https://nominatim.openstreetmap.org. So try it out.
With this release, Nominatim will use the osm2pgsql flex output per default for the OSM data input. If you use one of the default styles, the transition will be automatic. If you are working with custom style, you need to change to the flex lua format soon. The former osm2pgsql gazetteer output is now deprecated and support will be removed completely in version 5.0.
This release fixes a compatibility issue with the new PostGIS 3.4 release. If you plan to use PostGIS 3.4 or later, you must update to this latest release or Nominatim's address lookup tables will be corrupted.
A minimum version of 3.7 for Python and 7.3 for PHP is now required.
A more complete list of changes can be found in the Changelog.
Updating from any version between 3.6.x and 4.1.x to the new release is straightforward. Please follow the instructions from the migration guide. Updating from older versions is possible but not recommended. Please note that the migration to 4.3.0 requires building a new index needed by the frontend. It is therefore not recommended to migrate while a machine is in active use.