# Identify obsolete API between Unity versions

> Identify and fix API issues when you move a project to a more recent Unity version.

Some Unity API becomes obsolete between versions of the Unity Editor. When you migrate a project to a more recent Editor version, obsolete API can block compilation, or warn you that an API is nearing the end of support.

To identify obsolete API:

1. In the Project Auditor window, select the [**Code** view](/engine/6000.6/manual/analysis/project-auditor/window/code-view-reference.md).
2. In the **Areas** filter, select the **Upgrade** checkbox.
3. In the **Show** filter, select the **Upgrade Recommendations** checkbox.
4. In the **Target version** dropdown, select the Unity version you want to upgrade this project to.

Obsolete APIs appear in the **Issue** list. To learn how to upgrade a specific obsolete API, select the warning in the issues list and review the **Recommendation** section for next steps.

## Additional resources

* [Run Project Auditor from the command line](/engine/6000.6/manual/analysis/project-auditor/programming/run-from-command-line.md)
* [`Report` API documentation](/engine/6000.6/script-reference/unity/projectauditor/editor/report.md)