This is a bug fix release with some minor improvements of place node and address handling on import and during search.
This release also fixes a potential crash of the update process when handling addr:interpolation updates with an illegal value. Therefore, all users who run regular updates are strongly encourage to update to this latest release.
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.
Update: tarballs for version 4.1.1 from nominatim.org accidentally contained a more recent version. If you have installed such a tarball, your database will report as version 4.1.99. The additional changes are not problematic and your database is still fine. Please update to version 4.2.0 to get back to standard release versioning.