Project webhook changelog

When I get a webhook for an issue_update , one of the properties of the body is a changelog key where the changes are described

 "changelog": {
        "id": "14508",
        "items": [{
            "field": "priority",
            "fieldtype": "jira",
            "from": null,
            "fromString": null,
            "to": "1",
            "toString": "Highest"

however, on a project update, there is no changelog.

Is there any reason for this difference ?

In the UI, JIRA Issues have history. And, in the REST API, Issues have the changelog. As such, the information exists to send in the webhook. In contrast, Projects don’t have history in the UI or changelog in the REST API; hence, the information isn’t available for the webhook. For that matter, Issues are pretty much the exception.

I’m not sure that’s exactly a reason (since it’s a bit of a circular argument). But, if you need the changelog information, let’s flip this question around into a feature request.