Openconnect 5.01 no longer connects

[Anton Keks]

Hello and happy holidays!

we are sorry to inform that we have an Anyconnect server that worked
perfectly with openconnect 4.07, but no longer works with openconnect
5.01.
We discovered it after upgrade to Ubuntu 13.10. Downgrading
openconnect back to 4.07 solves the issue.

By not working I mean it cannot estabilish the conneciton, but it
doesn't give any meaningful error messages except for "connection
failed" after the password has been entered.

Which debugging info can I provide in order to trace this problem?

Anton