# What changed in cloudpickle

> 9 changes in cloudpickle 2 to 3 from its official release notes, upgrade guides and advisories: 2 breaking, 1 new APIs and options. Each one cited. Sources checked 2026-10-27. HTML: https://unstale.sh/pypi/cloudpickle/

To see which of these apply to a repository, run `npx @unstale/cli init` in it.

## cloudpickle 3

### Breaking changes

- Python 3.12 is officially supported, and Python 3.6 and 3.7 are no longer supported. (3.0.0) — [upgrade guide](https://github.com/cloudpipe/cloudpickle/blob/v3.0.0/CHANGES.md)

### Fixes and other changes

- Fixes pickling of dataclasses and their instances. (3.0.0) — [upgrade guide](https://github.com/cloudpipe/cloudpickle/blob/v3.0.0/CHANGES.md)

## cloudpickle 2

### Breaking changes

- Python 3.5 is no longer supported. (2.0.0) — [release notes](https://github.com/cloudpipe/cloudpickle/blob/HEAD/CHANGES.md)

### New APIs and options

- Register modules for by-value serialization so code defined in local modules can be serialized and executed remotely without those modules installed on the remote machine. (2.0.0) — [release notes](https://github.com/cloudpipe/cloudpickle/blob/HEAD/CHANGES.md)

### Fixes and other changes

- Handles the deprecation of co_lnotab in Python 3.10 and later. (2.0.0) — [release notes](https://github.com/cloudpipe/cloudpickle/blob/HEAD/CHANGES.md)
- Fixes a side effect that altered dynamic modules at pickling time. (2.0.0) — [release notes](https://github.com/cloudpipe/cloudpickle/blob/HEAD/CHANGES.md)
- Suppresses a source of non-determinism when pickling dynamically defined functions. (2.0.0) — [release notes](https://github.com/cloudpipe/cloudpickle/blob/HEAD/CHANGES.md)
- Adds support for pickling and depickling these OrderedDict views, following the strategy used for vanilla Python dictionaries. (2.0.0) — [release notes](https://github.com/cloudpipe/cloudpickle/blob/HEAD/CHANGES.md)
- Uses stricter detection heuristics to limit false positives. (2.0.0) — [release notes](https://github.com/cloudpipe/cloudpickle/blob/HEAD/CHANGES.md)