QGIS 4.0 is the biggest release in the project's history, and it arrived in February 2026 after years of preparation. The headline change is invisible: a migration from the Qt5 interface framework to Qt6, which modernises the codebase and unlocks better performance and high-DPI display support, but also breaks compatibility with many older plugins.

The most visible new feature is the 3D Globe View, carried over from QGIS 3.44, which renders the whole planet on an ellipsoid with 3D Tiles and point clouds. It turns QGIS into a credible globe-scale visualisation tool, and it pairs with the existing 3D map view for local scenes. Point cloud handling has also improved, with faster rendering and better editing tools.

For most users the practical question is not what is new but what breaks. Plugins written for QGIS 3.x need updating for Qt6, and some popular ones were slow to migrate. If your workflow depends on a specific plugin, check its compatibility before upgrading. The Processing Toolbox, the field calculator and the core geoprocessing tools all work, but the plugin ecosystem is still catching up.

The safe route for production work is to stay on QGIS 3.44, the final 3.x long-term release, until QGIS 4.2 arrives as the next long-term release in October 2026. Long-term releases get a year of bug fixes and are the version most organisations standardise on. Run 4.0 alongside 3.44 on a test machine, try your plugins and your typical projects, and move over when your own workflow is verified, not when the release notes say so.

If you do upgrade, back up your profiles and custom expressions first, export your processing models, and test one real project end to end before committing. The upgrade itself is free, as always, and the 4.0 release is a genuine step forward. But in GIS, a stable workflow beats a new feature list, and the long-term release exists precisely so you do not have to choose between them.