What's Changed Add CC to extra_env_vars for OS.UNKNOWN by @connorjward in https://github.com/firedrakeproject/firedrake/pull/5116 Fix release workflow by @connorjward in https://github.com/firedrakeproject/firedrake/pull/5120 Fix argument ordering in a SLATE test by @connorjward in https://github.com/firedrakeproject/firedrake/pull/5113 Enable setting the base for a PR using labels by @connorjward in https://github.com/firedrakeproject/firedrake/pull/5121 Fix compositions with RestrictedFunctionSpace by @pbrubeck in https://github.com/firedrakeproject/firedrake/pull/5126 Restructure CI configs to allow for more coverage by @connorjward in https://github.com/firedrakeproject/firedrake/pull/5117 Add schedule for PETSc Firedrake '26 by @pbrubeck in https://github.com/firedrakeproject/firedrake/pull/5128 Fix push testing CI workflow by @connorjward in https://github.com/firedrakeproject/firedrake/pull/5131 Fix multidomain form data by @pbrubeck in https://github.com/firedrakeproject/firedrake/pull/5132 Fix coarse_mat_type in notebook by @pbrubeck in https://github.com/firedrakeproject/firedrake/pull/5138 Links to Firedrake26 tutorial notebooks by @pbrubeck in https://github.com/firedrakeproject/firedrake/pull/5149 Fix Real + interior facet for PCPatch by @connorjward in https://github.com/firedrakeproject/firedrake/pull/5142 AuxiliaryOperatorSNES by @JHopeCollins in https://github.com/firedrakeproject/firedrake/pull/5119 docs: Update Jack's page on Rwanda workshop by @JDBetteridge in https://github.com/firedrakeproject/firedrake/pull/5160 firedrake-run-split-tests: fall back when GNU parallel is missing by @cpjordan in https://github.com/firedrakeproject/firedrake/pull/5147 Add outer timeout for mpi testing by @cpjordan in https://github.com/firedrakeproject/firedrake/pull/5150 Fix SLATE test for pytest 9.1.0 by @connorjward in https://github.com/firedrakeproject/firedrake/pull/5179 Add Irksome to firedrake-zenodo as an optional component by @connorjward in https://github.com/firedrakeproject/firedrake/pull/5182 Assemble interpolates with Indexed arguments by @leo-collins in https://github.com/firedrakeproject/firedrake/pull/5166 Demo about Reynolds-robust Navier-Stokes by @pefarrell in https://github.com/firedrakeproject/firedrake/pull/5163 Fix Adjoint + Fieldsplit by @pbrubeck in https://github.com/firedrakeproject/firedrake/pull/5197 Add concept of 'retired' configs to firedrake-configure by @connorjward in https://github.com/firedrakeproject/firedrake/pull/5153 Fixes for irksome zenodo releases by @connorjward in https://github.com/firedrakeproject/firedrake/pull/5196 Increase docs build retention from 1 to 5 days by @connorjward in https://github.com/firedrakeproject/firedrake/pull/5198 Remove misleading link to Jupyter website by @connorjward in https://github.com/firedrakeproject/firedrake/pull/5202 replace notebooks with jupytext by @danshapero in https://github.com/firedrakeproject/firedrake/pull/5195 Tweak mesh size used in Re-robust Navier-Stokes demo by @pefarrell in https://github.com/firedrakeproject/firedrake/pull/5200 Fix linkcheck by @connorjward in https://github.com/firedrakeproject/firedrake/pull/5222 Allow in place operators to modify coordinates by @dham in https://github.com/firedrakeproject/firedrake/pull/5214 AGENTS.md by @pbrubeck in https://github.com/firedrakeproject/firedrake/pull/5219 Improve firedrake-run-split-tests by @connorjward in https://github.com/firedrakeproject/firedrake/pull/5232 SLATE: Fix codegen for elimination of 1x1 block by @pbrubeck in https://github.com/firedrakeproject/firedrake/pull/5205 Add information about hwloc env variable that breaks users installs by @connorjward in https://github.com/firedrakeproject/firedrake/pull/5229 Refactor test parameterization for some IO tests by @connorjward in https://github.com/firedrakeproject/firedrake/pull/5203 firedrake-configure: scope apt HDF5 to --with-hdf5-* and declare zlib1g-dev by @timCorintis in https://github.com/firedrakeproject/firedrake/pull/5240 Support 64-bit integer builds by @leo-collins in https://github.com/firedrakeproject/firedrake/pull/5259 Make the PETSc/wheel optimisation flags overridable in firedrake-configure by @timCorintis in https://github.com/firedrakeproject/firedrake/pull/5253 Do not use LDFLAGS+= in firedrake-configure, it doesn't exist by @connorjward in https://github.com/firedrakeproject/firedrake/pull/5280 fix flaky test by @leo-collins in https://github.com/firedrakeproject/firedrake/pull/5282 Fixes for BDDC by @pbrubeck in https://github.com/firedrakeproject/firedrake/pull/5152 Fix Netgen permutation by @pbrubeck in https://github.com/firedrakeproject/firedrake/pull/5034 Fix for complex BDDC by @pbrubeck in https://github.com/firedrakeproject/firedrake/pull/5286 Skip adaptive BDDC elasticity test in complex mode; fix skipcomplex reason display by @pbrubeck in https://github.com/firedrakeproject/firedrake/pull/5291 Fix firedrake-configure for macOS netCDF build failure by @connorjward in https://github.com/firedrakeproject/firedrake/pull/5299 macos fix firedrake-configure again (--download-pnetcdf) by @connorjward in https://github.com/firedrakeproject/firedrake/pull/5303 Fix linting of Dockerfile by @connorjward in https://github.com/firedrakeproject/firedrake/pull/5304 Increase iteration counts for flaky test by @connorjward in https://github.com/firedrakeproject/firedrake/pull/5307 Speed up our slowest test by @connorjward in https://github.com/firedrakeproject/firedrake/pull/5318 Add a demo on Carstensen-Gedicke lower bounds for the Dirichlet Poisson eigenproblem by @pefarrell in https://github.com/firedrakeproject/firedrake/pull/5308 Quash some warnings by @connorjward in https://github.com/firedrakeproject/firedrake/pull/5316 Increase default timeout for firedrake-run-split-tests to 1 hour by @connorjward in https://github.com/firedrakeproject/firedrake/pull/5330 Fix HypreADS for fieldsplit by @connorjward in https://github.com/firedrakeproject/firedrake/pull/5328 Fix DG injection for symmetric tensors by @pbrubeck in https://github.com/firedrakeproject/firedrake/pull/5351 zero initial guess for Riesz Map solve by @JHopeCollins in https://github.com/firedrakeproject/firedrake/pull/5357 Add Fedora 44 community arch by @connorjward in https://github.com/firedrakeproject/firedrake/pull/5352 Fix linkcheck by @connorjward in https://github.com/firedrakeproject/firedrake/pull/5359 Fix linkcheck by @connorjward in https://github.com/firedrakeproject/firedrake/pull/5369 Constrain Cython to <3.3.0 due to petsc4py build error by @connorjward in https://github.com/firedrakeproject/firedrake/pull/5376 Cap islpy below 2026.2 on release by @pbrubeck in https://github.com/firedrakeproject/firedrake/pull/5378 check periodicity from unique mesh in ASMExtrudedStarPC by @JHopeCollins in https://github.com/firedrakeproject/firedrake/pull/5384 Add AC to team website by @achanbour in https://github.com/firedrakeproject/firedrake/pull/5387 Fix docs makefile to automatically regenerate authors list by @achanbour in https://github.com/firedrakeproject/firedrake/pull/5388 AGENTS.md: more patterns/antipatterns by @pbrubeck in https://github.com/firedrakeproject/firedrake/pull/5344 Fix repeated assembly of Real one forms by @connorjward in https://github.com/firedrakeproject/firedrake/pull/5393 Remove dead link by @connorjward in https://github.com/firedrakeproject/firedrake/pull/5397 Fix macOS for release by @connorjward in https://github.com/firedrakeproject/firedrake/pull/5389 plotting extruded meshes by @danshapero in https://github.com/firedrakeproject/firedrake/pull/5368 Update PETSc version to 3.25.5 for release by @connorjward in https://github.com/firedrakeproject/firedrake/pull/5417 Minor firedrake-zenodo fixups by @connorjward in https://github.com/firedrakeproject/firedrake/pull/5419 Use libsupermesh release by @connorjward in https://github.com/firedrakeproject/firedrake/pull/5422 Add pygraphviz back to CI and Docker by @connorjward in https://github.com/firedrakeproject/firedrake/pull/5423 RieszMap: allow passing options_prefix for solver by @JHopeCollins in https://github.com/firedrakeproject/firedrake/pull/5424 New Contributors @timCorintis made their first contribution in https://github.com/firedrakeproject/firedrake/pull/5240 Full Changelog: https://github.com/firedrakeproject/firedrake/compare/2026.4.1...2026.4.2