Summary of Major Changes Between Python Versions (2026 Update)

[u/nicholashairs]

Hi r/python 👋

Another year, another version of Python, and yet more features to guess which version of Python they belong to 😵‍💫

I've updated my "one page" Summary of Major Changes Between Python Versions for Python 3.15 and hope that it continues to be a useful resource for the community 😊

This summary is human typed/copied from the official release notes.

[u/Matthew_Summons]

I think it’d be easier to read if the latest versions were on top

[u/nicholashairs → u/Matthew_Summons]

I have thought about this a few times. Part of the reason I've kept it chronological is that one of the ways I use it is to read what I have available rather than what's recent.

It would be nice if my blog software allowed both, but alas I'm not going to fork it.

[u/nicholashairs → u/Matthew_Summons]

I've added a table of contents as a work around :)

[u/cipri_tom → u/Matthew_Summons]

I liked the chronological order

[u/ranisalt → u/cipri_tom]

Never thought before: sorting

[u/Hesirutu]

Typo:  sentinal

[u/nicholashairs → u/Hesirutu]

🤦‍♂️ I don't even know how I managed to make that typo happen... I even remember fixing a misspelling when it originally read "Sentinels".

Which even now my phone dictionary is like "did you mean Sentinals?"

Well at least you know it's natural stupidity instead of AI.

[u/SuggestionUpbeat2443 → u/nicholashairs]

> Compact annotion of generic classes and functions

Noticed this one too, but love this!

[u/nicholashairs → u/SuggestionUpbeat2443]

Fixed thanks!

[u/deadeye_82_1]

Huh, i didn't know that iterable unpacking is allowed in for-loops:

for x in *a, *b:
  print(x)

[u/frou → u/deadeye_82_1]

Interesting. The reasons keep coming to stop bothering with itertools.chain

[u/deadeye_82_1 → u/frou]

Another reason: https://docs.python.org/3/whatsnew/3.15.html#whatsnew315-unpacking-in-comprehensions

[u/Khavel_dev]

The 3.10 to 3.11 jump was the one that actually changed my daily work. The speed improvements and the much better error messages made an immediate difference without touching any code. 3.12's f-string changes (nested quotes, backslashes) sound minor but they removed a bunch of ugly workarounds I had everywhere. Good resource, bookmarked.

[u/Trang0ul]

Nice compilation, thank you! Besides admiring how Python has (and is) evolving, it can be used as a handy reference for updating old code.

[u/cipri_tom]

Thank you!

[u/SonixDream]

Thank you.

[u/RevRagnarok]

Thanks; very useful! I jumped from 2.7 to like 3.9 so was reading up on a few things like contextvars that don't seem to be very mainstream and I never saw them being announced.

[u/TerranceTorrance]

Really useful!

[u/Deno_Voku]

Thank you! There's always more to learn in Python!

[u/k1v1uq]

Another thanks!

[u/OpenComplaint524]

This summary is super handy, especially for keeping track of recent syntax changes and performance improvements. Bookmarked, thanks for putting this together!

[u/victotronics]

TIL "self-documenting f-strings".

Thanks!

[u/RevRagnarok → u/victotronics]

Great for debug, but then not as useful if you decide to enforce "no f-strings in logging calls" which is generally a good policy... :/

[u/nicholashairs → u/[deleted]]

Fixed thanks!

[u/nicholashairs → u/[deleted]]

I've added a table of contents instead :)