Toolchain progress updates, covering the public availability of experimental GNU toolchain builds for Windows on Arm64 and timelines for native compilation and Cygwin cross-toolchains.
Celebration of Python 3.15 native-by-default release on Windows on Arm, cross-organizational collaboration, and ongoing efforts to automate ecosystem package tracking.
Ecosystem status updates, PyArrow maintainer funding, alongside native PostgreSQL support status inquiries.
Approvals were completed and the public repository for experimental GNU toolchain weekly builds for Windows on Arm64 is live on the Arm GitHub organization, currently providing cross-toolchains for Linux and macOS.
Python 3.15 has officially achieved native-by-default support on Windows on Arm.
Python package ecosystem maintenance tracking: What we have for Cryptography could be extended to compare WoA vs Windows x86 build status at scheduled interval & flag discrepancy for investigation.
httptools and mysqlclient libraries have been enabled for Windows on Arm since the previous meeting.
PyArrow: Fathi from Linaro fully occupied on other projects, so responding on his patches would take a while --> can hand off to Microsoft team that has availability
[Deferred] Maintainer funding for PyArrow still under discussion.
Gleb K.
Share the what he has for the automated GitHub Actions wheel build monitoring.
(DONE) Send an email to the internal Microsoft team to coordinate the PyArrow handoff from Linaro.
Grant L.
(Shared for feedback) Build a prototype tool or dashboard to automate tracking of Python package Arm enablement and maintainer maturity.
Nathalie C.
Thomas D.
Reach out to Mayank to get the latest status on native PostgreSQL support for Windows on Arm and request inclusion in communications with Dave Kramer.
Patches for native toolchain compilation are scheduled for submission by the end of November, with upstreaming targeting December or January.
Delivery of a native toolchain for MinGW and a cross-toolchain for Cygwin is targeting end of the year.
Fathi may return to address comments on his PyArrow patches in the future once current project commitments conclude.
Ecosystem enablement topics & outstanding PR list to be discussed in a future meeting when Mayank is available.
GNU Toolchain Updates
Toolchain builds for Linux and macOS are currently available for download.
Arm has received all necessary approvals and published the experimental GNU toolchain repository on the Arm organization on GitHub.
Weekly experimental builds are automatically generated every Saturday directly from upstream commits without downstream patches.
Upstreaming of patches for native compilation is tracking for submission by late November, with upstream integration expected in December or January.
Delivery of a native toolchain for MinGW and a cross-toolchain for Cygwin is targeted by the end of the year to streamline testing and unblock GNU-dependent downstream projects.
Python 3.15 Native-by-Default Release
Python 3.15 is now native-by-default on Windows on Arm, marking a major milestone for ecosystem maturity.
The achievement was recognized as a prime example of successful cross-industry collaboration among Microsoft, Arm, Qualcomm, and Linaro via CoreCollective.
Native execution delivers efficiency benefits across Windows on Arm environments, especially for developer tooling and agentic workflows that routinely spin up Python.
Ongoing efforts will focus on Python package enablement, though full parity with x64 is not required given legacy and obsolete packages.
PyArrow
Upstream PyArrow maintainers lack funding for review bandwidth. The community has sufficient engineering resources to submit lots of PRs.
Microsoft is evaluating funding mechanisms internally to help alleviate maintainer bandwidth constraints, with outcomes pending.
Linaro engineering contributions from Fathi have paused due to his full allocation to other projects, though he may return to address feedback comments on his patches later.
Microsoft has an internal engineering team prepared to take up PyArrow work, and Gleb K. will make the intro for hand-off from Fathi via email.
Python Package Ecosystem Automation and Tracking
Microsoft is developing an automated workflow to monitor approximately 80 packages with wheel builds that have GitHub Actions, expanding on the monitoring model used for cryptography.
Workflows will run on a schedule comparing Windows on Arm builds against Windows x86 builds.
Any failure specific to Windows on Arm will trigger automated issue updates across package-specific tracking issues under a master issue.
Overall top 1000 downloaded package enablement currently stands at 86%, which is down from before because the top 1000 list is based on downloads, so WoA-enabled packages might drop off & new ones replacing them. httptools and mysqlclient enabled since the prior meeting.
Grant L. will prototype an automated dashboard to track package maturity from initial enablement to maintainer-owned maintenance, avoiding manual tracking across repositories.
PostgreSQL Native Support
Arm received another internal request regarding native PostgreSQL support on Windows on Arm.
The most recent correspondence between Mayank and Dave Cramer at PostgreSQL indicates Dave does not directly manage Arm build generation, leaving unresolved technical issues as of September 2026.
Native PostgreSQL progress remains stalled after initial assessment 18 months ago; Thomas D. will follow up with Mayank to obtain current status and join the discussion thread.