I have created a site off a domain, logged in a user and inserted a content version, in soap and javascript, and the attached file appears in salesforce classic chatter. However, ideally, I want to insert an attachment, so it shows up under a related list in account, but when setting Parent Id in JavaScript, an exception is thrown: attachment: Bad Field names on insert/update call: ParentId. I read recently that soap calls are now restricted and we cannot insert attachments, as witnessed by the exception. Is there some way I can let a soap user upload an attachment so that the parent record can be set? In my case, set to an account record. Need I try sending attachments as an email and make a trigger on emails received to insert an attachment?