Version 2026.1.28 (released on 28 January 2026)

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11.1. Version 2026.1.28 (released on 28 January 2026)#

This release introduces significant STEBBS enhancements, physics improvements for dyOHM calculations, executable documentation examples, and extensive stability fixes for QGIS/UMEP integration.

Major Features:

STEBBS Time-Varying Profiles: Added support for 10-minute profiles for Heating setpoints, Cooling setpoints, Appliance usage, Occupants, and Hot Water demand. This enables more realistic diurnal variation in building energy simulations. (#1038)
Dynamic OHM Surface Separation: Separated surfaces for dyOHM (dynamic Objective Hysteresis Model) calculation, allowing more accurate surface heat storage modelling for different land cover types. (#1122)
Executable Documentation: Added sphinx-gallery for executable documentation examples, enabling tutorial scripts that generate output and plots during documentation builds. (#1057)

Stability Improvements:

Thread-Safe Error Logging: Added modState parameter for thread-safe error handling, preventing race conditions in parallel simulations. (#1083)
QGIS Crash Fix: Removed stdout writes that caused QGIS to crash when running SUEWS through the UMEP plugin. (#1086)
Pandas 3.0 Compatibility: Fixed Copy-on-Write and asfreq() changes for forward compatibility with Pandas 3.0. (#1106)
QGIS/UMEP Test Suite: Added comprehensive compatibility test suite to catch integration issues early. (#905)

Physics Fixes:

Biogenic CO2: Fixed biogenic CO2 calculations to use local climate instead of global average temperature, improving FcRespi accuracy in regional studies. (#1117)
NumCapita Initialisation: Fixed uninitialised NumCapita variable that caused NaN values in CO2 flux calculations. (#1053)
Error Flag Reset: Reset error flag before kernel calls to prevent stale errors from previous runs affecting subsequent simulations. (#1109)

Validation Enhancements:

Land cover fraction check refactored to use Phase B as single authority (#1099)
Improved albedo ranges for physics-aware validation (#978)
Improved emissivity ranges for physics-aware validation (#979)
Added warning when surface fractions are auto-normalised (#1071)
Structured error handling with detailed validation reports (#1070)

Documentation:

Added user workflow guide for getting started with SUEWS (#1014)
Executable documentation examples using sphinx-gallery (#1057)

Build System:

Split make dev and make dev-dts targets for faster development builds when DTS components are unchanged (#1108)
Vendored f90wrap runtime to eliminate pip dependency conflicts (#963)
Fixed UMEP NumPy ABI compatibility for QGIS environments (#1056)
Fixed macOS UMEP wheel build by replacing sed with Python (#1128)
Added merge queue support to CI workflow (#954)
Removed format-master workflow incompatible with merge queue (#1130)
Replaced incremental DataFrame assignment with batch column creation (#1129)

Breaking Changes:

None. This release maintains full backward compatibility with 2025.11.20.

For complete details, see the CHANGELOG.