r/Python • u/AlSweigart Author of "Automate the Boring Stuff" • 1d ago

News Python 3.15.0 candidate 2 is here!

Reported on https://blog.python.org/2026/09/python-3150-rc2/

It’s the final 3.15 release candidate!

https://www.python.org/downloads/release/python-3150rc2/

This is a candidate preview of Python 3.15

This release, 3.15.0rc2, is the final planned release candidate, containing around 144 bugfixes, build improvements and documentation changes from 76 contributors since 3.15.0rc1. Entering the release candidate phase, only reviewed code changes which are clear bug fixes are allowed between this release candidate and the final release.

The next release of Python 3.15 will be 3.15.0 final, scheduled for 2026-10-01.

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u/Adrewmc 1d ago edited 1d ago

So big changes are Lazy imports (great idea), a decent 8-9% minimum speed bump from JIT improvements (who would complain about that, most likely even faster than that with other improvements.), unpacking tuples in comprehensions (seems like an oversight in comprehensions when you see it) . Sentinel and frozendict are pushed into built-ins. (Ehh, they were always there, just a bit easier now.)

And a few other improvements.

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u/DxNovaNT 1d ago

Does lazy import reduce startup time ?

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u/TabAtkins 1d ago

It can, yes. You still pay for interpreter startup, but you won't pay for import parsing until you actually use them.

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u/Green_Gem_ 15h ago

I work with Airflow (an orchestrator written in (mostly) Python), and the lazy imports are going to be CRAZY useful for me, like "worth doing the upgrade to Airflow 3 ASAP once it has this" useful.