--- title: The Mypy Blog: Mypy 2.4 Released | daily.dev description: Mypy 2.4.0 has been released with support for Python 3.15 features including PEP 661 sentinel types, PEP 810 lazy imports, and PEP 798 comprehension unpacking.... canonical: https://daily.dev/posts/the-mypy-blog-mypy-2-4-released-frfrx4bzr twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: The Mypy Blog: Mypy 2.4 Released | daily.dev og:description: Mypy 2.4.0 has been released with support for Python 3.15 features including PEP 661 sentinel types, PEP 810 lazy imports, and PEP 798 comprehension unpacking.... og:url: https://daily.dev/posts/the-mypy-blog-mypy-2-4-released-frfrx4bzr og:image: https://api.daily.dev/og/posts/FRfRX4BzR.png og:image:alt: The Mypy Blog: Mypy 2.4 Released og:image:width: 1200 og:image:height: 630 og:locale: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # The Mypy Blog: Mypy 2.4 Released **[mypy - Optional Static Typing for Python](https://daily.dev/sources/mypy-lang)** · 10 min read · 1 upvotes · 0 comments ## Summary Mypy 2.4.0 has been released with support for Python 3.15 features including PEP 661 sentinel types, PEP 810 lazy imports, and PEP 798 comprehension unpacking. The native parser (based on Ruff's parser) is now enabled by default, offering faster parsing and support for newer syntax regardless of target Python version, though it drops support for type comments on for/with statement variables. Parallel type checking is no longer experimental and now supports automatic worker count selection, delivering up to 5x speedups. The release also brings more lenient handling of variadic tuples with Any, substantial mypyc generator/coroutine performance improvements (over 2x faster on free-threaded builds), numerous crash fixes, and the removal of mypyc-accelerated wheels for macOS x86_64. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Questions this post answers ### What changed with the native parser becoming default in mypy 2.4? Mypy 2.4 enables the Ruff-based native parser by default instead of the legacy stdlib ast-based parser, making type checking significantly faster and enabling parallel checking. It also lets you target newer Python syntax (e.g. --python-version 3.15) while running mypy on an older Python version, and stub files can use newer syntax like PEP 695 generics. The legacy parser remains available via --no-native-parser but will be removed in early 2027. _Developers planning parser migrations before the 2027 removal can track mypy changes like this on daily.dev._ ### Does mypy 2.4 support Python 3.15's new sentinel type from PEP 661? Yes, mypy 2.4 supports PEP 661 sentinel values, which distinguish a missing argument from valid values like None. On Python 3.15 sentinel is a builtin; otherwise it is imported from typing_extensions. Mypy narrows the type correctly when checking identity with is or is not, and represents sentinels as first-class literal types. _Teams adopting Python 3.15 typing features can follow coverage like this on daily.dev._ ### How much faster is parallel type checking in mypy 2.4? Parallel type checking in mypy 2.4 is no longer experimental and delivers up to a 5x speedup when using 8 workers. You can manually specify worker count with -n8 or --num-workers 8, or use -n auto to automatically select workers based on available CPU cores, capped at 8 by default to limit memory use on large projects. _Developers tuning type-checking performance in CI can keep up with releases like this on daily.dev._ ## Similar posts on daily.dev - [Python 3.15 Hits Feature Freeze and Other News for June 2026 – Real Python](https://daily.dev/posts/python-3-15-hits-feature-freeze-and-other-news-for-june-2026-real-python-doxhua30e) · Real Python · 1 upvotes · 0 comments - [Python 3.15.0 beta 2 is here\!](https://daily.dev/posts/python-3-15-0-beta-2-is-here--byisq3xcx) · Python Insider · 5 upvotes · 0 comments --- Tags: [#general-programming](https://daily.dev/tags/general-programming), [#python](https://daily.dev/tags/python), [#performance](https://daily.dev/tags/performance) [View this post on daily.dev](https://daily.dev/posts/the-mypy-blog-mypy-2-4-released-frfrx4bzr) ```json {"@context":"https://schema.org","@graph":[{"@type":"Organization","@id":"https://daily.dev/#organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180},"sameAs":["https://twitter.com/dailydotdev","https://github.com/dailydotdev","https://www.linkedin.com/company/daily-dev-ltd"]},{"@type":"WebSite","@id":"https://daily.dev/#website","url":"https://daily.dev","name":"daily.dev","publisher":{"@id":"https://daily.dev/#organization"},"potentialAction":{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https://daily.dev/search?q={search_term_string}"},"query-input":"required name=search_term_string"}}]} {"@context":"https://schema.org","@type":"TechArticle","headline":"The Mypy Blog: Mypy 2.4 Released","url":"https://daily.dev/posts/the-mypy-blog-mypy-2-4-released-frfrx4bzr","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/the-mypy-blog-mypy-2-4-released-frfrx4bzr"},"datePublished":"2026-10-01T21:27:56.284Z","dateModified":"2026-10-01T21:28:34.274Z","description":"Mypy 2.4.0 has been released with support for Python 3.15 features including PEP 661 sentinel types, PEP 810 lazy imports, and PEP 798 comprehension unpacking....","image":"https://media.daily.dev/image/upload/s--qPvKM23u--/f_auto/v1722860399/public/Placeholder%2009","thumbnailUrl":"https://media.daily.dev/image/upload/s--qPvKM23u--/f_auto/v1722860399/public/Placeholder%2009","isAccessibleForFree":true,"articleSection":"mypy - Optional Static Typing for Python","inLanguage":"en","publisher":{"@type":"Organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180}},"author":{"@type":"Organization","name":"mypy - Optional Static Typing for Python","logo":"https://media.daily.dev/image/upload/logos/placeholder.jpg","url":"https://daily.dev/sources/mypy-lang"},"commentCount":0,"discussionUrl":"https://daily.dev/posts/the-mypy-blog-mypy-2-4-released-frfrx4bzr","interactionStatistic":[{"@type":"InteractionCounter","interactionType":{"@type":"LikeAction"},"userInteractionCount":1},{"@type":"InteractionCounter","interactionType":{"@type":"CommentAction"},"userInteractionCount":0}],"keywords":"general-programming,python,performance","timeRequired":"PT10M"} {"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https://daily.dev"},{"@type":"ListItem","position":2,"name":"mypy - Optional Static Typing for Python","item":"https://daily.dev/sources/mypy-lang"},{"@type":"ListItem","position":3,"name":"The Mypy Blog: Mypy 2.4 Released"}]} {"@context":"https://schema.org","@type":"FAQPage","@id":"https://daily.dev/posts/the-mypy-blog-mypy-2-4-released-frfrx4bzr#faq","mainEntity":[{"@type":"Question","name":"What changed with the native parser becoming default in mypy 2.4?","acceptedAnswer":{"@type":"Answer","text":"Mypy 2.4 enables the Ruff-based native parser by default instead of the legacy stdlib ast-based parser, making type checking significantly faster and enabling parallel checking. 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