# What changed in asyncer

> 10 changes in asyncer 0.0 from its official release notes, upgrade guides and advisories: 4 breaking, 1 deprecations, 1 new APIs and options. Each one cited. Sources checked 2026-11-13. HTML: https://unstale.sh/pypi/asyncer/

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

## asyncer 0.0

### Breaking changes

- Python 3.10 is no longer supported. (0.0.20) — [release notes](https://github.com/fastapi/asyncer/releases/tag/0.0.20)
- Support for asyncer-slim is dropped; use asyncer instead. (0.0.16) — [release notes](https://github.com/fastapi/asyncer/releases/tag/0.0.16)
- Support for Python 3.9 was dropped. (0.0.15) — [release notes](https://github.com/fastapi/asyncer/releases/tag/0.0.15)
- Support for Python 3.8 was dropped, so developers must use a newer Python version. (0.0.12) — [release notes](https://github.com/fastapi/asyncer/releases/tag/0.0.12)

### Deprecations

- asyncer-slim is deprecated and now only depends on asyncer, affecting developers who choose or depend on this package. (0.0.13) — [release notes](https://github.com/fastapi/asyncer/releases/tag/0.0.13)

### New APIs and options

- Adds the Agent Library Skill, installable with this command. (0.0.18) — [release notes](https://github.com/fastapi/asyncer/releases/tag/0.0.18)

### Tooling

- An official skill helps coding agents use new features and recommended patterns for the installed version; install it in a project with uvx library-skills. (0.0.19) — [release notes](https://github.com/fastapi/asyncer/releases/tag/0.0.19)

### Fixes and other changes

- Asyncer now supports Python 3.15 and 3.15t, expanding the Python versions developers can use. (0.0.19) — [release notes](https://github.com/fastapi/asyncer/releases/tag/0.0.19)
- Added sniffio to project requirements, so it is installed as a dependency. (0.0.11) — [release notes](https://github.com/fastapi/asyncer/releases/tag/0.0.11)
- Adds support for running asyncer with Python 3.14. (0.0.10) — [release notes](https://github.com/fastapi/asyncer/releases/tag/0.0.10)