How to add a comment to an attached file via REST API in Acumatica 2024 R1?

Hi everyone,

I'm currently working with Acumatica Cloud ERP 2024 R1 and using the REST API to manage file attachments on various documents (e.g., Sales Orders, Invoices, etc.).

What I can already do:

I’m successfully attaching files to entities using the files endpoint like this:

PUT /entity/Default/24.200.001/files/PX.Objects.AR.CustomerMaint/BAccount/{entityID}/{filename}

This works well — the file is successfully attached and visible under the Files tab on the customer screen.

What I want to do next:

I would like to add a comment to this file — just like you can do manually in the UI by entering a comment when attaching a file.

My assumption so far:

From what I understand, this may require two separate REST calls:

1. PUT — attach the file (already working ✅)

2. Some second request to update the file record and add a comment (❓)

But I haven't found a working REST example for that.

My Questions:

1. Is it possible to attach a comment to a file via REST API in Acumatica 2024 R1?

2. If yes — what is the recommended way or endpoint to do it?

3. If not directly supported — would it work via a custom endpoint?

Any help, tips, or examples would be very appreciated!

Thanks in advance,
Daria Maksymova