2026.4.1

What's Changed

• Update pyproject.toml by @connorjward in #5040
• fix linkcheck by @leo-collins in #5049
• Tighten tao tolerances in adjoint tests by @JHopeCollins in #5047
• Fix MG transfers for elements that need cell sizes by @pbrubeck in #5043
• Fix ASMStarPC on RestrictedFunctionSpace by @pbrubeck in #5046
• Use embedded transfer for HDiv/HCurl on manifolds by @pbrubeck in #5052
• Fix formatting in docs (visualisation.rst) by @juliusgh in #5065
• Add some demo test dependencies by @connorjward in #5066
• Fix website build by @connorjward in #5068
• Add slack invite to linkcheck skip by @connorjward in #5067
• stderr in firedrake-configure and Python version check by @connorjward in #5072
• Add rough agenda to Firedrake26 by @connorjward in #5075
• Fix for quadrature rule with mixed dimension macroelements by @pbrubeck in #5074
• bugfix: MixedCovariance.function_space property by @JHopeCollins in #5070
• Combat Zenodo rate limiting in firedrake-zenodo by @connorjward in #5032
• Refactor firedrake configure by @connorjward in #5073
• AssembledPC: fix sub_mat_type by @pbrubeck in #5079
• Stop propagating log messages to root logger. by @stephankramer in #5086
• Fix interpolation cell subset by @KarsKnook in #5087
• Fix IndexError in _pic_swarm_in_mesh on MPI ranks with empty cell partition by @hardik-corintis in #5078
• Remove team member broken link by @connorjward in #5088
• Submesh: support tuple subdomain_id by @pbrubeck in #5004
• Set upper limit on UFL version by @connorjward in #5096
• Fixes to firedrake-configure by @connorjward in #5094
• Add sponsored drinks reception to PETSc/Firedrake meeting schedule by @JDBetteridge in #5102
• Fixes for multidomain form preprocessing by @pbrubeck in #5089
• Use composite actions to clean up workflows by @connorjward in #5099
• Fix PR labeling triggering CI rerun by @connorjward in #5104
• SubmeshHierarchy by @pefarrell in #5083
• Remove dead link by @connorjward in #5108
• Try out reusable step for GPU CI run by @connorjward in #5103
• Fix cell_avg + MixedFunctionSpace by @pbrubeck in #5109
• Speed up CI setup and refactor PyPI publishing workflow by @connorjward in #5110
• Fix _SNESContext.options_prefix by @pbrubeck in #5092
• firedrake-configure options for Ubuntu 2026.04 by @JHopeCollins in #5085
• Cleanup up core.yml workflows by @connorjward in #5112

New Contributors

• @juliusgh made their first contribution in #5065
• @hardik-corintis made their first contribution in #5078

Full Changelog: 2026.4.0...2026.4.1