> This page is for SDKs, version Legacy.
> For other versions, use one of these documentation indexes:
> - Current (default): https://buildwithfern.com/learn/sdks/current/llms.txt
> - Legacy: https://buildwithfern.com/learn/sdks/legacy/llms.txt

> For clean Markdown content of this page, append .md to this URL. For the complete documentation index, see https://buildwithfern.com/learn/llms.txt.

## 4.61.0

**`(feat):`** Add support for `DATE_TIME_RFC_2822` primitive type. Fields with `format: date-time-rfc-2822`
in OpenAPI specs now generate as `Rfc2822DateTime` (a `datetime.datetime` subclass) that
parses RFC 2822 date strings (e.g., "Wed, 02 Oct 2002 13:00:00 GMT") using Python's
`email.utils.parsedate_to_datetime`. Compatible with both Pydantic V1 (`__get_validators__`)
and V2 (`__get_pydantic_core_schema__`), passing mypy strict type checking.

**`(fix):`** Fix code snippet generation for RFC 2822 datetime fields to use
`email.utils.parsedate_to_datetime()` with RFC 2822 format strings instead of
`datetime.fromisoformat()` with ISO 8601 format.

## 4.60.2

**`(fix):`** Fix `explode: false` query parameter serialization for array types. When an OpenAPI spec
sets `explode: false` on an array query parameter, the generated SDK now serializes values
as comma-separated strings (e.g. `tags=A,B,C`) instead of repeated keys (e.g. `tags=A&tags=B&tags=C`).
This applies to both regular and streaming endpoints.

## 4.60.1

**`(chore):`** Use generator-cli JS API directly instead of subprocess spawning.
Remove generator-cli from Docker image since it is now bundled via esbuild.