2026.4.0

What's Changed

Deprecations

• Adapt to UFL changing some methods to properties by @connorjward in #4629
• Remove deprecated adjoint backend usage by @connorjward in #4769
• Remove deprecated File alias for VTKFile by @connorjward in #4756
• Remove star imports from __init__.py by @leo-collins in #4722
• Remove bizarre cofunction init behaviour by @connorjward in #4754
• Rename 'unmarked' to 'UNMARKED' to make clear that it is a constant by @connorjward in #4837
• Remove deprecated BCs method attribute by @connorjward in #4822
• Drop utils.cached_property in favour of functools.cached_property by @nileshhadalgi016 in #4903
• Remove deprecated function space subfunctions by @connorjward in #4895
• Simplify MeshGeometry initialisation by @connorjward in #4583
• Deprecate WithGeometry.create factory function by @connorjward in #4957
• Prefer petsctools over pyop2.utils for certain utility methods by @connorjward in #5002
• Deprecate variable layer extrusion by @connorjward in #5028

Install

• Download MUMPS on Linux because PETSc now assumes a higher version by @JHopeCollins in #4661
• Clean up how we include package data in our distributions by @connorjward in #4755
• Explicitly link MPI in setup.py by @connorjward in #4762

VertexOnlyMesh/interpolation

• Stop renumbering arguments in the expression to interpolate by @leo-collins in #4582
• test assembly of composition of interpolates by @leo-collins in #4710
• Remove Interpolator from public API and other interpolation refactoring by @leo-collins in #4595
• Make assembly of interpolation matrices respect mat_type by @leo-collins in #4749
• interpolate two-forms by @leo-collins in #4770
• symbolic interpolation docs by @leo-collins in #4739
• multi-domain assembly by @leo-collins in #4763
• Assemble mixed cross-mesh interpolation operator by @leo-collins in #4792
• Leo/cross mesh non lagrange by @leo-collins in #4804
• Use Index_CreateWithArray to build mesh spatial index by @leo-collins in #4865
• Avoid creating a function space when calculating bounding box coordinates by @leo-collins in #4900

Adjoint/checkpointing

• Add per-rank disk checkpointing for adjoint tape by @sghelichkhani in #4891

Submesh

• Allow for solving multi-domain problems involving codim-0 submeshes by @ksagiyam in #3478
• Allow for solving multi-domain problems involving codim-1 submeshes by @ksagiyam in #4430
• Ksagiyam/support submesh assign by @ksagiyam in #4489
• Submesh on subcommunicator by @pbrubeck in #4761
• Submesh: relabel ghost entities as owned if comm.size == 1 by @pbrubeck in #4816
• Tidy up Submesh by @pbrubeck in #4999

Netgen

• Move Firedrake code from ngsPETSc into Firedrake by @connorjward in #4782
• Adaptive Multigrid by @pbrubeck in #4726
• Netgen: curved meshes from Mesh constructor and refine_marked_elements by @pbrubeck in #4930
• Add multigrid tests for Netgen SplineGeometry and CSGeometry by @pbrubeck in #5016

Covariance operator and ensemble

• Ensemble methods dispatch to MPI methods for non-Firedrake types by @JHopeCollins in #4580
• EnsembleBlockDiagonalMat and EnsembleBJacobiPC by @JHopeCollins in #4711
• White noise generators and AR covariance operators by @JHopeCollins in #4716
• Ensemble.sequential context manager by @JHopeCollins in #4964
• Move CovariancePC to top level namespace by @JHopeCollins in #5020
• MixedCovarianceOperator by @JHopeCollins in #5026
• autoregressive covariance: add custom weight for custom diffusion form by @JHopeCollins in #5027

Other

• LinearEigensolver: default to eps_target = 0 is conceptually wrong by @stefanozampini in #4634
• PMGPC: use native matrix-free (adjoint) interpolation by @pbrubeck in #4602
• ImplicitMatrixContext: create submatrix via MatCreateSubMatrixVirtual by @pbrubeck in #4693
• default firedrake options prefix for petsctools by @JHopeCollins in #4699
• Support MatIS and BDDC by @pbrubeck in #4405
• Mesh independent optimization trick by @jrmaddison in #4575
• Redesign how we interface with communicators and PETSc by @connorjward in #4766
• Function space method to create broken function space. by @JHopeCollins in #4773
• Ml mixed fs by @jshipton in #4795
• Tidy up custom exceptions by @leo-collins in #4834
• Interpolate into PhysicallyMappedElements by @pbrubeck in #4832
• FiredrakeException base class by @leo-collins in #4843
• fix zero-form interpolation by @leo-collins in #4841
• Multigrid: native transfers for non-Lagrange elements by @pbrubeck in #4839
• NonUniqueMeshSequenceError by @leo-collins in #4844
• Accept pathlib.Path objects as filename in Mesh by @ZiyaSelim in #4853
• Introduce runtime_quadrature_space by @pbrubeck in #4850
• Test BDFM by @pbrubeck in #4866
• Fix multidomain assign by @pbrubeck in #4849
• BDDC: cellwise subdomains, matfree MatIS, and user-defined primal vertices by @pbrubeck in #4757
• Fix assign for MixedFunctionSpace and correct 'ancester' typo by @sghelichkhani in #4888
• RestrictedFunctionSpace: support assignment across different restrictions by @pbrubeck in #4890
• Add deadlock safe function for calling fallible pieces of code on rank 0 by @connorjward in #4972
• Real x extruded fixes by @connorjward in #4970
• Fix Real coefficients in interior facet integrals by @sghelichkhani in #4992
• PCPatch: support exterior facet integrals by @miguelcoolchips in #4878
• Fix assembly of Real coefficients for interior facet integrals by @connorjward in #4996
• Refactor periodic utility meshes by @connorjward in #4836
• Loading of periodic meshes generated by gmsh by @miguelcoolchips in #4935
• Add CUDA configuration to firedrake-configure and github actions by @dsroberts in #4988
• Check that the mesh has a boundary before trying to apply a BC to it by @connorjward in #5014
• delay creation of multifunction by @dham in #5022
• Allow passing a maximum degree quadrature to a measure by @JHopeCollins in #4989
• Improved traceback from PETSc errors by @stefanozampini in https://github.com...

Firedrake: an automated finite element system

This release is specifically created to document the version of firedrake used in a particular set of experiments using Firedrake. Please do not cite this as a general source for Firedrake or any of its dependencies. Instead, refer to https://www.firedrakeproject.org/citing.html

2025.10.4

What's Changed

• Fix Docker builds by @connorjward in #4955
• Install build requirements in workflow now they aren't available by default by @connorjward in #4960
• Update notebooks repo at every push to release by @connorjward in #4958
• Fix Dockerfile ENV setting (export does not work) by @connorjward in #4966
• Update reference in demo by @ABaierReinio in #4967
• Add link to slides and code for Firedrake training event next week by @pefarrell in #4968
• Add zenodo to linkcheck ignore list by @connorjward in #4974
• Conference photo, light edits by @pefarrell in #4977
• Fix docstring for PeriodicBoxMesh by @connorjward in #4978
• Add extra detail about times and dates for Firedrake/PETSc 26 by @connorjward in #4990
• Add missing PetscFunctionBegin calls to tinyASM by @connorjward in #4997
• Add missing exercise 1 back into first notebook by @connorjward in #5013

Full Changelog: 2025.10.3...2025.10.4

2025.10.3

What's Changed

• Use PETSc.ScalarType(0) in Function.zero by @JHopeCollins in #4720
• Automatically update notebooks repository on push to release by @connorjward in #4639
• default firedrake options prefix for petsctools by @JHopeCollins in #4727
• Fix linkcheck by @connorjward in #4733
• BUG: Fix EquationBC + matfree + fieldsplit by @pbrubeck in #4734
• Multicomponent demo sub bcs for EquationBC by @KarsKnook in #4695
• BUG: use native prolongation for KMV elements by @pbrubeck in #4747
• Add HDF5 test to firedrake-check by @connorjward in #4759
• BUG: fix Function._ad_dot for H1 (#4590) by @stephankramer in #4760
• FML: fix dunder methods and support BaseForm by @pbrubeck in #4768
• Zenodo fixes by @connorjward in #4758
• BUG: Fix symmetry in supermeshing by @pbrubeck in #4764
• Add webpage about March tutorial by @pefarrell in #4793
• Fix docs for sphinx 9 by @connorjward in #4802
• Add a registration link for Oxford training event by @pefarrell in #4796
• FunctionSpace: enable variant and quad_scheme and docs by @pbrubeck in #4607
• Enable solve(a == 0, u) by @pbrubeck in #4805
• Update Firedrake 26 organising committee by @connorjward in #4813
• Skip timing out backwards compat io tests on CI by @JHopeCollins in #4818
• Fix for numpy 2.4.1 by @pbrubeck in #4824
• Fix typo in patch demos by @pbrubeck in #4826
• Purge the pip cache in CI by @connorjward in #4858
• More numpy 2.4.1 fixes by @pbrubeck in #4862
• MG: force injection into all levels with Real space unknown by @pbrubeck in #4864
• Fix for petsc4py/slepc4py+setuptools 81 by @connorjward in #4871
• setuptools fix for petsc4py+slepc4py in docker file by @JHopeCollins in #4875
• Speed up test collection by @connorjward in #4880
• PETSc/Firedrake meeting webpage by @dham in #4872
• fix accommodation dates by @dham in #4885
• Add contributing guide to website by @connorjward in #4877
• Draft schedule (#4894) by @pbrubeck in #4897
• Remove broken team member link by @connorjward in #4898
• Link to AI policy in contrib docs by @connorjward in #4910
• convert incorrect use of single backicks to double by @j-bowhay in #4916
• Fix dumpdir fixture by @connorjward in #4922
• Remove broken submesh example from docstring by @connorjward in #4928
• Improvements for plotting tests by @connorjward in #4927
• Fix deadlock when the compiler crashes internally by @connorjward in #4913
• Bugfix with deflation: only deflate successful solves by @pefarrell in #4933
• Trivial change to tutorial website: specify rooms by @pefarrell in #4936
• Fix stochastic PyOP2 test hang by @connorjward in #4937
• update adjoint notebook for api changes by @dham in #4945
• firedrake-zenodo 'fixes' by @connorjward in #4939
• Website edits: close registration by @pefarrell in #4947
• Use latest PETSc patch release by @connorjward in #4938

Full Changelog: 2025.10.2...2025.10.3

Firedrake: an automated finite element system

This release is specifically created to document the version of firedrake used in a particular set of experiments using Firedrake. Please do not cite this as a general source for Firedrake or any of its dependencies. Instead, refer to https://www.firedrakeproject.org/citing.html

2025.10.2

What's Changed

• Ignore flaky old hotel link by @connorjward in #4630
• Add [docs] dependency in developer install instructions by @pbrubeck in #4633
• replace obsolete intersphinx by @dham in #4141
• Add PyOP2 API docs back to conf.py by @connorjward in #4636
• fix test_high_order_location_warped_interior_facet by @leo-collins in #4632
• BUG: fix reuse of matfree adjoint Interpolator by @pbrubeck in #4623
• test: skip regression/test_locate_cell.py::test_high_order_location_e… by @ksagiyam in #4642
• Fix Hessian calculation for NonlinearVariationalSolver block by @JHopeCollins in #4641
• BUG: Fix TransferManager reuse on VectorFunctionSpace components by @pbrubeck in #4649
• BUG: fix multigrid transfers for symmetric tensors by @pbrubeck in #4648
• Attach appctx to DirichletBCs by @pbrubeck in #4655
• Ksagiyam/disable temp by @ksagiyam in #4658
• Firedrake container on ARM by @connorjward in #4640
• Bug: Fix bcs for BaseFormOperator on MixedFunctionSpace by @pbrubeck in #4659
• Fix linkcheck by @connorjward in #4681
• BUG: Fix FormSum involving the output tensor by @pbrubeck in #4670
• Multicomponent demo update (into release) by @ABaierReinio in #4676
• Specialise G-ADOPT smoke tests for main and release by @connorjward in #4680
• Fix Thetis smoke tests by @connorjward in #4686
• Fix firedrake-check: tweak locations for cell location tests by @connorjward in #4692
• PCPatch: validate mesh overlap by @pbrubeck in #4684
• Add information about building with non-system MPIs by @connorjward in #4698
• Fix subfunction hessian by @JHopeCollins in #4705
• Leo/authors by @leo-collins in #4704
• Remove mailing list information from the website by @connorjward in #4691
• Fix Hypre auxiliary spaces by @pbrubeck in #4712
• Make VTK optional again by @connorjward in #4713
• fix Function._ad_assign_numpy for real space in parallel by @JHopeCollins in #4714
• Fix point evaluation API change by @leo-collins in #4675
• Fix the bug in implementing the AuxiliaryOperatorPC and add a note in… by @Molin-Han in #4717

New Contributors

• @Molin-Han made their first contribution in #4717

Full Changelog: 2025.10.1...2025.10.2

Firedrake: an automated finite element system

This release is specifically created to document the version of firedrake used in a particular set of experiments using Firedrake. Please do not cite this as a general source for Firedrake or any of its dependencies. Instead, refer to https://www.firedrakeproject.org/citing.html

Firedrake: an automated finite element system

This release is specifically created to document the version of firedrake used in a particular set of experiments using Firedrake. Please do not cite this as a general source for Firedrake or any of its dependencies. Instead, refer to https://www.firedrakeproject.org/citing.html

2025.10.1

What's Changed

• Distinguish firedrake-configure links without leading to git conflicts by @connorjward in #4625
• pyproject.toml: add immutabledict by @ksagiyam in #4622
• Move ensemble parallelism links by @connorjward in #4626
• SLATE: prevent Cofunction reassembly by @pbrubeck in #4377

Full Changelog: 2025.10.0...2025.10.1

2025.10.0

What's Changed

Adjoint

• checkpointing bcs by @Ig-dolci in #4284
• Dham/abstract reduced functional by @dham in #3941

Interpolate/VertexOnlyMesh

• Dual interpolation from/into MixedFunctionSpace by @pbrubeck in #4197
• Cleanup Interpolate assembly by @pbrubeck in #4288
• Move __future__ interpolation into interpolation.py by @leo-collins in #4346
• Allow construction of interpolation matrix between a VertexOnlyMesh and its input-ordering by @leo-collins in #4341
• Make interpolate function avoid using Interpolator by @leo-collins in #4432
• Change VOM missing_points_behaviour API by @leo-collins in #4524
• Cell location on non-simplicial higher-order meshes by @leo-collins in #4517
• Fix for vom-to-vom permutation matrix on Vector-valued function spaces by @leo-collins in #4510
• Cell location on simplicial higher-order meshes by @leo-collins in #4484
• introduce PointEvaluator object by @leo-collins in #4516
• Remove Interpolator.interpolate by @leo-collins in #4531
• deprecate .at() by @leo-collins in #4543
• Warn users about interpolate expression renumbering by @leo-collins in #4572
• stop annotation inside PointEvaluator by @leo-collins in #4567
• Pass kwargs to Cofunction.interpolate by @pbrubeck in #4587
• Matfree adjoint interpolation by @pbrubeck in #4552
• Explicitly assemble the interpolate adjoint matrix by @pbrubeck in #4576
• MixedInterpolator by @pbrubeck in #4596

submesh

• submesh: allow for extracting codim-1 submeshes by @ksagiyam in #4329

petsctools

• Use petsctools package by @connorjward in #4194
• Import get_external_packages from petsctools not firedrake.petsc by @JHopeCollins in #4381
• Fixes for changes to petsctools OptionsManager API by @connorjward in #4418
• Use petsctools release by @connorjward in #4423
• Link to petsctools API documentation by @connorjward in #4569
• Use petsctools for citations by @connorjward in #4560

Ensemble

• EnsembleFunction and EnsembleFunctionSpace. by @JHopeCollins in #4025

Other

• BDDC: Fix block sizes by @pbrubeck in #4253
• Remove firedrake-install and friends by @connorjward in #4270
• Ksagiyam/rename sub elements by @ksagiyam in #4354
• use ufl.apply_coefficient_split() by @ksagiyam in #4349
• Speed up caching by @connorjward in #4383
• remove mesh.init() by @ksagiyam in #4201
• Change master to main (2) by @connorjward in #4445
• Stop casting Constants+domain to Real functions by @connorjward in #4497
• TSFC: Improved caching to remove ComponentTensors by @pbrubeck in #4503
• Avoid dat_version increment with riesz_representation("l2") by @jrmaddison in #4504
• Expunge Vector by @connorjward in #4499
• fix snes_linesearch_type l2 -> secant by @ksagiyam in #4525
• RestrictedFunctionSpace: support Fieldsplit, multigrid, and python PC by @pbrubeck in #4169
• FixAtPointBC: support bendy meshes by @pbrubeck in #4532
• MG: rediscretize with a different coarse_mat_type by @pbrubeck in #4538
• Extruded plotting fixes by @danshapero in #4553
• Add support for deflation via firedrake.DeflatedSNES by @pefarrell in #4558
• Fix coarsening for R space by @pbrubeck in #3814
• delete _from_cell_list by @leo-collins in #4557
• Coarsen SLATE Tensors by @pbrubeck in #2889
• VariationalSolver: support sub_mat_type by @pbrubeck in #4028
• Fix TransferManager reuse for mixed coefficients by @pbrubeck in #4600

Full Changelog: 2025.4.3...2025.10.0