The QGIS development team has officially announced plans for QGIS 4.0, with an expected release in October 2025 following QGIS 3.44. This major update centers on modernizing the platform's core infrastructure.

Core Upgrade

The foundational Qt framework will transition from Qt 5 to Qt 6. This shift prioritizes long-term maintainability while delivering significant performance and security enhancements. QGIS 4.0 will retain deprecated APIs to ease plugin developer migration—requiring minimal code adjustments for Qt6 compatibility while preparing for future versions.

Why Upgrade Now?

  • Qt 5.15 End-of-Support: Extended support for Qt 5.15 terminates in May 2025. Security patches beyond this date will be exclusive to commercial license holders, limiting community access to critical updates.
  • Qt6 Maturity: Projects like QField and Mergin Maps already demonstrate Qt6's production readiness in geospatial applications. Migration ensures alignment with modern frameworks and unlocks new capabilities in rendering, UI responsiveness, and performance optimization.

Version Strategy

  1. Extended LTR Support: QGIS 3.40 LTR's maintenance period extends by 4 months to May 2026, granting plugin developers and organizations additional adaptation time.
  2. QGIS 4.0 Release: Target launch October 2025 as a regular feature release.
  3. Next LTR: QGIS 4.2 will become the subsequent Long-Term Release in February 2026.

Technical Implications

Remember the QGIS 2 to 3 transition? While QGIS 4.0 aims for smoother migration than its predecessor, compatibility challenges remain likely. As an early adopter, I'll upgrade immediately—both to explore new features and gain native Apple Silicon support (current QGIS runs via Rosetta translation on M-series Macs).