Why Flexy 205 doesn't support SFTP?

I am using Flexy 205 connected to an industrial PLC. I want to store the acquired data to a server that our company uses. However the server is SFTP, not FTP. We have tried the data transfer but there was an error. Then I had found this topic: Customer Ciber - Flexy 205 FTPS
I understand the Flexy 205 doesn’t support SFTP, but now I need to explain this within the company. Can you provide a technical reason that why Flexy doesn’t support SFTP, only FTP? Thanks in advance.

The reason that I was given was that there was not a big enough demand from customers for it to be added. I would encourage you to contact sales in your region to formally request it be added.

What type of server? Could you use MQTT, OPC UA, Modbus, or some other protocol?

Is SFTP already supported for the Flexy 205? Last post was from Dec. 2020.
Please advise.

Right now the flexy only support FTP.