# Proposal: Officially Deprecate Support for Legacy (Single-Phase Init) Extension Modules

**URL:** <https://discuss.python.org/t/proposal-officially-deprecate-support-for-legacy-single-phase-init-extension-modules/89262>\
**Category:** Core Development\
**Created:** [April 22, 2025, 11:31pm UTC](https://discuss.python.org/t/proposal-officially-deprecate-support-for-legacy-single-phase-init-extension-modules/89262 "2025-04-22T23:31:07Z")\
**Posts on this page:** 1\
**Showing post:** 46

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**Author:** ![encukou](https://sea2.discourse-cdn.com/flex002/user_avatar/discuss.python.org/encukou/32/2461_2.png) [@encukou](https://discuss.python.org/u/encukou)\
**Post date:** [May 29, 2025, 11:30am UTC](https://discuss.python.org/t/proposal-officially-deprecate-support-for-legacy-single-phase-init-extension-modules/89262/46 "2025-05-29T11:30:12Z")

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For the record: [PR #134764](https://github.com/python/cpython/pull/134764) proposes to document single-phase init as _legacy_.  
I think that matches the consensus here, but, I’m obviously biased.

The only reason to use single-phase init should be backwards compatibility. It can be a very strong reason, of course.

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_[View the full topic](https://discuss.python.org/t/proposal-officially-deprecate-support-for-legacy-single-phase-init-extension-modules/89262)._