Feature first available:
iPECS Cloud version 5.0.
This feature allows the 1000i series of LIP phones to use TCP as the transport mode for call setup / notification / status. The initial intent is to address some rare cases where there are lost packets or NAT table timeouts. In the long run, this will be the basis for supporting TLS encryption of this channel.
This setting can be toggled between UDP and TCP in the Customer Manager interface under User Setup, then Device at the bottom of that page.