Creating Document Revision with REST v11

Hello, 
I'm new to SugarCRM 13 and am running into some issues converting what we had in 6.5 to 13. I have many REST calls that use to create documents and document revisions. 

According to the new Endpoints, there doesn't seem to be one to create document revisions. 

I tried to follow this guide with the document module: https://support.sugarcrm.com/Documentation/Sugar_Developer/Sugar_Developer_Guide_13.0/Cookbook/Web_Services/REST_API/PHP/How_to_Manipulate_File_Attachments/index.html

however, it always gives this error:

(
[error] => missing_parameter
[error_message] => Attachment is missing
)

I'm setting the <attachment field> to "filename" like the example. Should I be using something else for the document module? or is there another way to upload files to the documents module.

I am calling "Documents/<id>/file/filename" and have removed the content type from my headers.

Any help would be appreciated