I'm not able to update a Draft version using REST API, as it's described in: https://github.com/ezsystems/ezpublish-kernel/blob/6.7/doc/specifications/rest/REST-API-V2.rst#update-version

Steps:
1. Login as admin,
2. Start creating a new folder
3. Set name field to “TestDraft” and Save draft (don’t publish). Note the assigned ContentID
4. Send a REST request:

POST

{domain}/api/ezp/v2/content/objects/{ContentID}/versions/1

Accept: application/vnd.ez.api.Version+xml
X-CSRF-Token: I’m logging in by sending a POST request to {domain}

/api/ezp/v2/user/sessions and saving the token value
X-HTTP-Method-Override: PATCH
Content-Type: application/vnd.ez.api.VersionUpdate+xml

Request body:
in the attachment

Expected outcome:
in the response the name field is updated to "TestDraftEdited", as specified in the request body

Actual:
Endpoint returns code 200, with modification date set to "now". Field still has old value. (see response_body.xml)