> This page is for SDK.

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

## 5.41.1

**`(fix):`** Models that keep unknown JSON keys no longer keep one that matches a declared field except for case
(e.g. `VALUE` next to `value`). Such a key used to be sent again after the declared field, so a
case-insensitive decoder on the receiving end (e.g. Go's `encoding/json`) read it instead of the
field's value. Other unknown keys (e.g. `brand_new_field`) are still kept and sent as before.