First of all, we recognize that the transitions from Pydantic V1 to V2 has been and will be painful for some users. We're sorry about this pain , it was an unfortunate but necessary step to correct design mistakes of V1.
There will not be another breaking change of this magnitude!
Active development of V1 has already stopped, however critical bug fixes and security vulnerabilities will be fixed in V1 for one year after the release of V2 (June 30, 2024).
We will not intentionally make breaking changes in minor releases of V2.
Methods marked as
deprecated will not be removed until the next major release, V3.
Of course some apparently safe changes and bug fixes will inevitably break some users' code — obligatory link to XKCD.
The following changes will NOT be considered breaking changes, and may occur in minor releases:
- Changing the format of
refas used in JSON Schema.
- Changing the
typewill not change — if you're programmatically parsing error messages, you should use
- Adding new keys to
ValidationErrorerrors — e.g. we intend to add
column_numberto errors when validating JSON once we migrate to a new JSON parser.
- Adding new
repreven of public classes.
In all cases we will aim to minimize churn and do so only when justified by the increase of quality of
pydantic for users.
Pydantic V3 and beyond¶
We expect to make new major releases roughly once a year going forward, although as mentioned above, any associated breaking changes should be trivial to fix compared to the V1-to-V2 transition.
Support for Python versions¶
Pydantic will drop support for a Python version when the following conditions are met:
- The Python version has reached EOL.
- <5% of downloads of the most recent minor release need to be using that version.