Release 2026.09.05

Upgrade instructions

From #7492 (Enable AhA/B adaptive angular resolution in BBH pipeline):

AhA/B horizon adaptivity is now enabled by default in generated BBH inspiral input files.
To disable it manually, edit the generated input file and remove the Criteria entries under ApparentHorizons: ObservationAhA and ObservationAhB.

From #7533 (Upgrade black Python formatting):

Rerun pip install -r support/Python/dev_requirements.txt in your Python env (or enable SPECTRE_FETCH_MISSING_DEPS) to upgrade your installed black version.

Merged pull-requests (25)

General changes (23):

• Apply FixToAtmosphere to ValenciaDivClean reconstruction (#7495)
• Add ZernikeB2 support to power monitors (#7493)
• Add ModalTimeSeriesReader (#7389)
• GH TimeDerivative Optimizations (#7369)
• Support LDG infrastructure part six (#7501)
• Add B3 Power Monitors (#7509)
• Add UpdateAuxiliaryVariables for SecondOrderScalarWave (#7514)
• Add filled option to nonconforming sphere (#7503)
• Use cylinders instead of cubed cylinders in CBCO (#7479)
• Add half-fourier basis (#7387)
• Import initial orbital params from SimulationSupport instead of SpEC (#7512)
• Enable AhA/B adaptive angular resolution in BBH pipeline (#7492)
• Fix some link dependencies and increase a test timeout (#7522)
• Clean up leftover files in TestReadH5 setup (#7532)
• Add erichury to Authors.Contributors in Metadata.yaml (#7530)
• Add BoundaryCondition base class for SecondOrderScalarWave system (#7518)
• Enable commented-out boundary correction tests (#7534)
• Create equal rate region generator to handle both subcell and nonconforming interfaces (#7519)
• Upgrade black Python formatting (#7533)
• Use CMake presets (#7320)
• Update coefficients in ScriObserveInterpolated.cpp (#7531)
• Add Lax-Friedrichs flux for the LDG system SecondOrderScalarWave (#7520)
• Fix CCE regression test (#7538)

Build system (1):

• Fix compiling with gcc 15, nvcc 13 (#7521)

Continuous integration & deployment (1):

• Release workflow: overwrite existing version draft (#7515)

Contributors (11): @EmilyWang0130, @nilsvu, @michaeldmurphy1, @nikwit, @hen-w, @macedo22, @erichury, @kidder, @wthrowe, @GitHimanshuc, @nilsdeppe