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Python syntax and features timeline

See how Python has changed, one useful feature at a time.

Explore Python 3.6–3.15 in release order. Each lesson explains when features arrived, why you might use them, and which mistakes to avoid. This is a curated guide; the linked official release notes cover the full changelog.

Know Python variables, conditions, loops, and functions before starting. New to Python? Start with Foundations. Older release entries explain history rather than recommend installing an unsupported version.

1. December 23, 2016

   Python 3.6: Readable formatting and annotations

   F-strings put values beside their labels, annotations document variables, and underscores make numeric literals easier to read.

   • F-strings: expressions inside text
   • Variable annotations document intent
   • Underscores in numeric literals

   Editorial review October 25, 2026 · Official release notes

2. June 27, 2018

   Python 3.7: Less boilerplate and predictable order

   Dataclasses describe records, dictionary insertion order becomes a language guarantee, and asyncio gains a simpler entry point.

   • Dataclasses for small records
   • Dictionary insertion order is guaranteed
   • asyncio.run() owns the event loop

   Editorial review October 25, 2026 · Official release notes

3. October 14, 2019

   Python 3.8: Assign inside expressions when it helps

   The walrus operator can reuse a computed value, positional-only parameters clarify APIs, and f-strings can label debugging values.

   • The := walrus operator
   • Positional-only parameters with /
   • Self-labeling f-strings with =

   Editorial review October 25, 2026 · Official release notes

4. October 5, 2020

   Python 3.9: Convenient collections and exact text removal

   Merge dictionaries with explicit precedence, annotate built-in collections, and remove a whole prefix or suffix without strip confusion.

   • Dictionary union with |
   • Type hints with list[str] and dict[str, int]
   • Remove a prefix or suffix exactly

   Editorial review October 25, 2026 · Official release notes

5. October 4, 2021

   Python 3.10: Match data shapes and make contracts explicit

   Structural matching handles shapes, type unions become shorter, and strict zip catches accidentally mismatched inputs.

   • Structural pattern matching
   • Union types with X | Y
   • zip(strict=True) checks lengths

   Editorial review October 25, 2026 · Official release notes

6. October 24, 2022

   Python 3.11: Handle grouped failures and inspect errors

   Exception groups, structured async tasks, TOML parsing, and more precise tracebacks improve everyday diagnostics.

   • ExceptionGroup and except*
   • TaskGroup gives related tasks a boundary
   • Read TOML with tomllib
   • Tracebacks can point inside expressions

   Editorial review October 25, 2026 · Official release notes

7. October 2, 2023

   Python 3.12: Cleaner generics and fewer f-string restrictions

   Type parameters and type aliases gain dedicated syntax; f-strings accept more ordinary Python expressions.

   • Type parameters and type aliases
   • F-strings accept more expression syntax

   Editorial review October 25, 2026 · Official release notes

8. October 7, 2024

   Python 3.13: New defaults, record updates, and interpreter options

   Type parameters can have defaults, copy.replace() updates supported records, and CPython experiments with execution models.

   • Default values for type parameters
   • copy.replace() updates supported records
   • A more capable interactive shell
   • Experimental free-threading and JIT

   Editorial review October 25, 2026 · Official release notes

9. October 7, 2025

   Python 3.14: Separate interpolation from rendering

   Template strings retain values for processing; annotations defer evaluation; native concurrency options continue evolving.

   • Template strings with a t prefix
   • Annotations are evaluated when needed
   • Multiple interpreters through the standard library
   • Free-threading becomes supported

   Editorial review October 25, 2026 · Official release notes

10. October 9, 2026

    Python 3.15: New ways to defer work and model values

    Explicit lazy imports, comprehension unpacking, sentinel values, immutable mappings, and UTF-8 defaults expand the language toolkit.

    • Explicit lazy imports
    • Unpacking inside comprehensions
    • A sentinel distinguishes missing from None
    • An immutable mapping with frozendict
    • UTF-8 becomes the default text encoding

    Editorial review October 25, 2026 · Official release notes