REST API v2 - Upload problem - multiple revisions

[ac]

I have a problem uploading multiple revisions of the same file (i.e. attaching a file to a workspace/item). A new file works fine, the same does the second revision of the file. However, upload of the third revision always seem to fail.

I start uploading a new file with the following API call and JSON FileUploadRequest:

POST https://contex.autodeskplm360.net/api/v2/workspaces/29/items/2897/files

{"fileName":"Demo1.jpg","title":"Demo1","description":"Uploaded from Contex"}

This works fine and I get the usual JSON file collection in return.

Then I do a checkout and a second upload of the same file using the same JSON FileUploadRequest:

POST https://contex.autodeskplm360.net/api/v2/workspaces/29/items/2897/files/99/checkout 

POST https://contex.autodeskplm360.net/api/v2/workspaces/29/items/2897/files/99/checkin

This also works fine and I get an updated JSON file object in return.

Finally I repeat the checkout/checkin sequence for the third revison of the file now using the file ID of the second revision:

POST https://contex.autodeskplm360.net/api/v2/workspaces/29/items/2897/files/100/checkout
POST https://contex.autodeskplm360.net/api/v2/workspaces/29/items/2897/files/100/checkin

The checkout works fine i.e. I get status CHECKEDOUT in return (the file also shows up checked out on the PLM web page).
However, the upload/checkin fails with the following strange JSON response leaving the file checked out:

{"errorCode":"UNKNOWN","message":"Unknown error.","params":null,"url":null,"errorClass":"APIError"}

I have also tried using the original file id (99 in this example) for the second revision chekcout, but then the checkout fails with errorcode FILE_CHECKOUT_FAILED as I would expect.

Am I doing something wrong or is there an API problem with multiple file revisions?

[gasevsm]

Please specify the version number in your payload with every call to create a new version. Let me know how this works,

[ac]

When you say payload, do you mean the JSON object sent with the checkin command?

I have tried the following JSON without luck:

{"fileName":"PageDropDemo7.jpg","title":"PageDropDemo7","description":"Uploaded from PageDrop","version":3}

In return I get:

{"errorCode":"GEN_EMPTY_INPUT","message":"Empty input.","params":null,"url":null,"errorClass":"APIError"}