> ## Documentation Index
> Fetch the complete documentation index at: https://docs.ionq.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Migrating from old versions

### Breaking changes

* Body has been renamed to `input`, and is always a JSON payload. The `format` field in input replaces lang as a means of controlling what kind of input is being run.
* Results are no longer served alongside the job body when fetching jobs; now use the results\_url field to fetch.
* *(v0.1 only)* **Calibrations** endpoints has been deprecated in favor of [Characterizations](/api-reference/v0.3/characterizations).

### New features

* Error mitigation is now controllable via API. Debiasing can improve performance via randomized qubit mappings and intelligent post-processing of noise.
* Ability to specify target hardware generation on Job creation. (e.g. `qpu.forte-1`)

## Non-breaking changes

* Histogram example expanded to include scientific notation for a JSON numeric value.