in an effort to standardize all post parameters in the REST v1 API to use snake_case names, we have deprecated the bodyOnly flag in the wikitext to HTML transform end point [1]. Instead, clients should use body_only, as mentioned in the documentation.

We plan to remove support for the old form by the end of November.

Thanks,

Gabriel

[1]: https://en.wikipedia.org/api/rest_v1/?doc#!/Transforms/post_transform_wikitext_to_html_title_revision