Yes, lemm.ee has all the standard Lemmy features. However, the format for this request has changed, and it seems the app has not been updated yet.
For technical context: your app is trying to use the singular post_id
field when marking posts as read. This field was marked as deprecated several releases ago, as it was replaced by a post_ids
array field, in order to enable marking multiple posts as read at the same time. The deprecated post_id
field has been removed in Lemmy 0.19.4.