Hi Klaus,
I have read the wiki doc, and this may be a problem using a voip app, which is expected always active, as our fixed phone, when We are in mobility.

I have also read in internet for other possibilities regarding a solution of this limitation, but the one proposed by apple, using the push kit, for me, not represent the best solution at all:
- Need always an internet connection available
- I think, not observe the privacy policies (the app need to communicate with anAPN Apple, which We don't know how really work and which information is maintained), and in any case is out of "our" control or customer control, which, I think, may prefer to trust with a known supplier and best if the supplier is european.

For this reason I think may be better to have a different solution.
I have also read from Apple developer guide, that there might be a chance, using some feature provided by "Background Execution".

I don't know exactly if this may be a way to resolve the problem and how this may create some discrepancy from the "standard" always followed by Innovaphone in their solution and if this may create some problem to the supported RFC's.

I hope to have Your's opinion on this.

I really think this is a big limitation to voip services

Thank You for Your prompt reply and I hope other users have an opinion on this.

Best regards