save draft error in customer interface

I'm running osTicket v1.14.5.

In the customer interface, the following error is displayed when the customer is adding a reply to a ticket:

undefined:
Unable to save draft.Refresh the current page to restore and continue your draft.

That error does not occur when staff is adding a reply to a ticket.

Please help. Thanks.

1.14.5 is really old, please upgrade and see if it fixes the issue.