Get user attribute names

> ### Use contexts instead > > After you have upgraded your LaunchDarkly SDK to use contexts instead of users, you should use [Get context attribute names ](https://launchdarkly.com/docs/api/contexts/get-context-attribute-names) instead of this endpoint. Get all in-use user attributes in the specified environment. The set of in-use attributes typically consists of all attributes seen within the past 30 days.