Synchronizing modified files already saved to ownclould

Sorry, this is my first time using this site for help. The issues I have is that I have install ownclod 9.1 with client version 2.4.0.8894. All new file syncs without issues. The only issues I had is that after it upload/sync to server, if I make a modification to the client files. It does not sync with the server even if you force the sync. Still does not sync the files that have been modified. So if the next client open the file it does not have the correct version of the documents. If any one can point in the right direction it would be greatly appreciated.

Thanks,

Mark Vang