Quick update, I had the same issue "this version of the client is invalid. please download a new version or perform a liveupdate" and this is the response I have received from the Betamax (INTERVOIP) helpdesk.
Thank you for reporting this issue! We are currently looking into the matter and hope to have it resolved as soon as possible. Please try again at a later time.
Our apologies for any inconvenience caused.