# Python 3.15 reaches its first release candidate and freezes the ABI > Python 3.15's first release candidate marks an ABI stability milestone and asks package maintainers to publish wheels ahead of the final release. Canonical URL: https://www.devobs.io/news/news-python-315-rc1-wheel-readiness/ By: Ines Costa Published: 2026-09-06T11:58:54.644Z Updated: 2026-09-06T11:58:54.644Z Event date: 2026-08-04 Section: Languages Python released 3.15.0rc1 on August 4, moving the upcoming feature series into its release-candidate phase. The [release page](https://www.python.org/downloads/release/python-3150rc1/) says the ABI will no longer change within the series and calls on package maintainers to publish compatible wheels. ## The packaging milestone changes the task Only reviewed changes that clearly fix bugs are intended between the candidate and final release. Python says wheels built against these release candidates will work with future 3.15 versions, while continuing to advise against production use of the preview interpreter. For extension maintainers, that shifts attention from exploratory compiler compatibility toward distributable artifacts. A successful build on one development machine is only the beginning. The package's supported operating systems, architectures, and interpreter variants each need an explicit coverage decision. ## Make downstream testing possible A useful readiness report lists which wheels exist, which platforms still build from source, and which combinations remain untested. Consumers can then decide whether a failure belongs to the interpreter, the package, or an absent artifact, instead of rediscovering the same packaging gap independently. Test installation in an environment that cannot fall back unnoticed to a source build. Then execute representative functionality, rather than treating installation success as evidence that every native path works. Keep the wheel filename and interpreter identity in the result so an issue report is reproducible. The release candidate also offers a deadline for documenting unresolved compatibility limits. A narrowly stated limitation is actionable for downstream maintainers; an unqualified claim of support is difficult to use when only part of the distribution matrix has been exercised. ## Source references -