Hey ibrahima,
Unfortunately that is not possible to make it compatible with FFMpeg older version is because each of the FFMpeg version has different command structure.
If you would like us to assist you to update this, we actually got the service for setup this FFmpeg on the server, you can contact us at helpdesk
https://crm.stackideas.com but we need to check first and see whether possible to update FFMpeg to 2.8.x version on your server.