This release fixes some bugs with the Nominatim CLI tool and the reverse API and adds small improvements to the database processing.
The release also extends support for the new Lua flex-style import scripts. There are now style implementations for all the standard styles of Nominatim available, which can be used as a base for customization. Please note that the changes are incompatible with the lua scripts from 4.2.1. If you have used older scripts, copy flex-base.lua into your project directory before upgrading.
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.