I assume: based on the thread, you are talking about Cisco AnyConnect VPN client.
I recently updated all client from version 2.2 to version 2.5.
Following is my way and it is working for me.
First you need to downnload the package from Cisco.
Second, you use ASDM to upload the package to the ASA
Third, I SSH into the ASA and changed a line
webvpn
enable outside
svc image disk0:/anyconnect-win-2.5.0217-k9.pkg <<<<-- change this line.
svc enable
save the config and that was what I did. There may be other way to do it with the ASDM. But this was the way I did and it works.
Hope this help!