Warning: GDAL 3.6.0 has officially been retracted and is superseded per GDAL 3.6.1. GDAL 3.6.0 which could cause corruption of the spatial index of GeoPackage files it created (in tables with 100 000 features or more): cf https://github.com/qgis/QGIS/issues/51188 and https://github.com/OSGeo/gdal/pull/6911. GDAL 3.6.1 fixes that issue. Setting OGR_GPKG_ALLOW_THREADED_RTREE=NO environment variable (at generation time) also works around the issue with GDAL 3.6.0. Users who have generated corrupted GeoPackage files with 3.6.0 can regnerate them with 3.6.1 with, for example, "ogr2ogr out_ok.gpkg in_corrupted.gpkg" (assuming a GeoPackage file with vector content only)

• CMake is the only build system available in-tree. autoconf and nmake build systems have been removed
• OpenFileGDB: write and update support (v10.x format only), without requiring any external dependency, with same (and actually larger) functional scope as write side of the FileGDB driver
• RFC 86: Column-oriented read API for vector layers. Implemented in core, Arrow, Parquet, GPKG and FlatGeoBuf drivers
• Add read/write raster JPEGXL driver for standalone JPEG-XL files. Requires libjxl
• Add KTX2 and BASISU read/write raster drivers for texture formats. Require (forked) basisu library
• Vector layer API: table relationship discovery & creation, Upsert() operation
• GeoTIFF: add multi-threaded read capabilities (requires NUM_THREADS open option or GDAL_NUM_THREADS configuration option to be set)
• Multiple performance improvements in GPKG driver
• ogr_layer_algebra.py: promoted to official script (#1581)
• Code linting and security fixes
• Bump of shared lib major version
• Full release notes at https://github.com/OSGeo/gdal/blob/v3.6.0/NEWS.md