Problem using openconnect to log into University VPN

[Daniel Suson]

To whom it may concern,

     I have used openconnect to log into my University's VPN from my 
Linux computer for a few years without a problem. Approximately at the 
start of this year, the IT department made some sort of change (I think 
they updated the Cisco VPN server, but m not sure) and I have not been 
able to connect to the VPN. When I try to use openconnect, I get the 
following error string:

> root at My-Computer:~# openconnect --protocol=anyconnect {VPN-DNS}
> POST {VPN-DNS}
> Connected to {VPN-IP}
> SSL negotiation with {VPN-DNS}
> Connected to HTTPS on {VPN-DNS} with ciphersuite 
> (TLS1.2)-(ECDHE-SECP256R1)-(RSA-SHA512)-(AES-256-GCM)
> Got HTTP response: HTTP/1.1 404 Not Found
> Unexpected 404 result from server
> GET {VPN-DNS}
> Connected to {VPN-IP}
> SSL negotiation with {VPN-DNS}
> Connected to HTTPS on {VPN-DNS} with ciphersuite 
> (TLS1.2)-(ECDHE-SECP256R1)-(RSA-SHA512)-(AES-256-GCM)
> Got HTTP response: HTTP/1.0 302 Object Moved
> GET {VPN-DNS}+webvpn+/index.html
> SSL negotiation with {VPN-DNS}
> Connected to HTTPS on {VPN-DNS} with ciphersuite 
> (TLS1.2)-(ECDHE-SECP256R1)-(RSA-SHA512)-(AES-256-GCM)
> Got HTTP response: HTTP/1.1 301 Moved Permanently
> GET {VPN-DNS}+CSCOU+/anyconnect_unsupported_version.html
> Please upgrade your AnyConnect Client
> Failed to complete authentication
I have the anyconnect client on a Windows computer and have been able to 
successfully connect to {VPN-DNS} using that, but I need to be able to 
use it on my Linux computer. My IT folks aren't very helpful, simply 
telling me that I need to use either the Linux version of anyconnect or 
use my Windows computer. Unfortunately, I run Slackware Linux and Cicso 
only supports Ubuntu. Amy suggestions on how to get openconnect working 
again are greatly appreciated.

Sincerely,

Dan