Vodafone canceled the the call afer 2 min. because of missing keep alive action

[lucchinelli]

Hi IP-tel.
I am using vodafone as my phone providor and an ip native dsl connect. So the phone calls are VoIP based.
Now I want to use my account on my mobile phone with sipdoid. It works very fine but after 2 min. Vodafone canceled the call. I find out that is a knowing issue because they want a keep alive message from the client and if there is no they cancel the call.
I found a Informationen about this issue in a vodafone forum from 2013: “your app (sipdroid) does not support keep alive with option messages. If there is no answered we disconnect the call (rfc 3261)“
They argue that this is mandatory for providor in germany.
Do you support this feature or can you fix this problem?
Thanks in advance.
Marco