Version Compatibility
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!
Pydantic V1 Support¶
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.
Pydantic V2 Changes¶
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
ref
as used in JSON Schema. - Changing the
message
andcontext
fields ofValidationError
errors,type
will not change — if you're programmatically parsing error messages, you should usetype
. - Adding new keys to
ValidationError
errors — e.g. we intend to addline_number
andcolumn_number
to errors when validating JSON once we migrate to a new JSON parser. - Adding new
ValidationError
errors. - Changing
repr
even of public classes.
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.