The only way to recover was to reboot the Vera from Settings / Net and WiFi.
Once I did this, the Elk devices report back again, sensor changes are coming in.
02 01/03/16 21:46:13.116 luup_log:237: ElkPlugin::handlerFunc Message type description: Zone Change Update <0x2f175680>
02 01/03/16 21:46:13.116 luup_log:237: ElkPlugin::processZoneChangeUpdate: Zone #1, status = Normal. <0x2f175680>
02 01/03/16 21:46:13.117 luup_log:237: ElkPlugin::setZoneState: Set variable ‘Armed’ = ‘1’ for zone 1 (device 245). <0x2f175680>
02 01/03/16 21:46:13.119 luup_log:237: ElkPlugin::setZoneState: Set variable ‘Tripped’ = ‘0’ for zone 1 (device 245). <0x2f175680>
02 01/03/16 21:46:13.691 luup_log:237: ElkPlugin::checkMessage: length=25(0x19), message type=KC, data=‘0100000000001111111’, misc=00, checksum=10 <0x2f175680>
02 01/03/16 21:46:13.692 luup_log:237: ElkPlugin::handlerFunc Message type description: Keypad KeyChange Update <0x2f175680>
02 01/03/16 21:46:13.693 luup_log:237: ElkPlugin::setPartitionState: Set variable ‘ChimeEnabled’ = ‘0’ for partition 1 (device 244). <0x2f175680>
02 01/03/16 21:46:13.821 luup_log:237: ElkPlugin::checkMessage: length=10(0x0A), message type=ZC, data=‘001A’, misc=00, checksum=C0 <0x2f175680>
02 01/03/16 21:46:13.822 luup_log:237: ElkPlugin::handlerFunc Message type description: Zone Change Update <0x2f175680>
02 01/03/16 21:46:13.822 luup_log:237: ElkPlugin::processZoneChangeUpdate: Zone #1, status = Violated. <0x2f175680>
02 01/03/16 21:46:13.823 luup_log:237: ElkPlugin::setZoneState: Set variable ‘Tripped’ = ‘1’ for zone 1 (device 245). <0x2f175680>
02 01/03/16 21:46:13.841 luup_log:237: ElkPlugin::checkMessage: length=11(0x0B), message type=PC, data=‘A0301’, misc=00, checksum=96 <0x2f175680>
02 01/03/16 21:46:13.841 luup_log:237: ElkPlugin::processMessage: Unhandled message type ‘PC’ <0x2f175680>
02 01/03/16 21:46:15.331 luup_log:237: ElkPlugin::checkMessage: length=11(0x0B), message type=PC, data=‘A0501’, misc=00, checksum=94 <0x2f175680>
02 01/03/16 21:46:15.332 luup_log:237: ElkPlugin::processMessage: Unhandled message type ‘PC’ <0x2f175680>
02 01/03/16 21:46:16.681 luup_log:237: ElkPlugin::checkMessage: length=10(0x0A), message type=ZC, data=‘0013’, misc=00, checksum=CE <0x2f175680>
02 01/03/16 21:46:16.681 luup_log:237: ElkPlugin::handlerFunc Message type description: Zone Change Update <0x2f175680>
02 01/03/16 21:46:16.682 luup_log:237: ElkPlugin::processZoneChangeUpdate: Zone #1, status = Normal. <0x2f175680>
02 01/03/16 21:46:16.683 luup_log:237: ElkPlugin::setZoneState: Set variable ‘Armed’ = ‘1’ for zone 1 (device 245). <0x2f175680>
02 01/03/16 21:46:16.684 luup_log:237: ElkPlugin::setZoneState: Set variable ‘Tripped’ = ‘0’ for zone 1 (device 245). <0x2f175680>
02 01/03/16 21:46:23.231 luup_log:237: ElkPlugin::checkMessage: length=22(0x16), message type=XK, data=‘1239211030116010’, misc=00, checksum=77 <0x2f175680>
02 01/03/16 21:46:23.232 luup_log:237: ElkPlugin::handlerFunc Message type description: Ethernet Module Test <0x2f175680>
02 01/03/16 21:46:42.951 luup_log:237: ElkPlugin::checkMessage: length=25(0x19), message type=KC, data=‘0100000000001111111’, misc=00, checksum=10 <0x2f175680>
02 01/03/16 21:46:42.952 luup_log:237: ElkPlugin::handlerFunc Message type description: Keypad KeyChange Update <0x2f175680>
02 01/03/16 21:46:42.953 luup_log:237: ElkPlugin::setPartitionState: Set variable ‘ChimeEnabled’ = ‘0’ for partition 1 (device 244). <0x2f175680>
02 01/03/16 21:46:53.251 luup_log:237: ElkPlugin::checkMessage: length=22(0x16), message type=XK, data=‘4239211030116010’, misc=00, checksum=74 <0x2f175680>
02 01/03/16 21:46:53.252 luup_log:237: ElkPlugin::handlerFunc Message type description: Ethernet Module Test <0x2f175680>
02 01/03/16 21:47:11.421 luup_log:237: ElkPlugin::checkMessage: length=25(0x19), message type=KC, data=‘0100000000001111111’, misc=00, checksum=10 <0x2f175680>
02 01/03/16 21:47:11.422 luup_log:237: ElkPlugin::handlerFunc Message type description: Keypad KeyChange Update <0x2f175680>
02 01/03/16 21:47:11.423 luup_log:237: ElkPlugin::setPartitionState: Set variable ‘ChimeEnabled’ = ‘0’ for partition 1 (device 244). <0x2f175680>
02 01/03/16 21:47:23.271 luup_log:237: ElkPlugin::checkMessage: length=22(0x16), message type=XK, data=‘1240211030116010’, misc=00, checksum=7F <0x2f175680>
02 01/03/16 21:47:23.272 luup_log:237: ElkPlugin::handlerFunc Message type description: Ethernet Module Test <0x2f175680>
02 01/03/16 21:47:40.581 luup_log:237: ElkPlugin::checkMessage: length=25(0x19), message type=KC, data=‘0100000000001111111’, misc=00, checksum=10 <0x2f175680>
02 01/03/16 21:47:40.582 luup_log:237: ElkPlugin::handlerFunc Message type description: Keypad KeyChange Update <0x2f175680>
02 01/03/16 21:47:40.583 luup_log:237: ElkPlugin::setPartitionState: Set variable ‘ChimeEnabled’ = ‘0’ for partition 1 (device 244). <0x2f175680>
02 01/03/16 21:47:53.281 luup_log:237: ElkPlugin::checkMessage: length=22(0x16), message type=XK, data=‘4240211030116010’, misc=00, checksum=7C <0x2f175680>
02 01/03/16 21:47:53.282 luup_log:237: ElkPlugin::handlerFunc Message type description: Ethernet Module Test <0x2f175680>
02 01/03/16 21:48:09.701 luup_log:237: ElkPlugin::checkMessage: length=25(0x19), message type=KC, data=‘0100000000001111111’, misc=00, checksum=10 <0x2f175680>
02 01/03/16 21:48:09.702 luup_log:237: ElkPlugin::handlerFunc Message type description: Keypad KeyChange Update <0x2f175680>
02 01/03/16 21:48:09.703 luup_log:237: ElkPlugin::setPartitionState: Set variable ‘ChimeEnabled’ = ‘0’ for partition 1 (device 244). <0x2f175680>
02 01/03/16 21:48:23.311 luup_log:237: ElkPlugin::checkMessage: length=22(0x16), message type=XK, data=‘1241211030116010’, misc=00, checksum=7E <0x2f175680>
02 01/03/16 21:48:23.312 luup_log:237: ElkPlugin::handlerFunc Message type description: Ethernet Module Test <0x2f175680>
02 01/03/16 21:48:38.871 luup_log:237: ElkPlugin::checkMessage: length=25(0x19), message type=KC, data=‘0100000000001111111’, misc=00, checksum=10 <0x2f175680>
02 01/03/16 21:48:38.872 luup_log:237: ElkPlugin::handlerFunc Message type description: Keypad KeyChange Update <0x2f175680>
02 01/03/16 21:48:38.873 luup_log:237: ElkPlugin::setPartitionState: Set variable ‘ChimeEnabled’ = ‘0’ for partition 1 (device 244). <0x2f175680>
02 01/03/16 21:48:53.331 luup_log:237: ElkPlugin::checkMessage: length=22(0x16), message type=XK, data=‘4241211030116010’, misc=00, checksum=7B <0x2f175680>
02 01/03/16 21:48:53.332 luup_log:237: ElkPlugin::handlerFunc Message type description: Ethernet Module Test <0x2f175680>
02 01/03/16 21:49:08.051 luup_log:237: ElkPlugin::checkMessage: length=25(0x19), message type=KC, data=‘0100000000001111111’, misc=00, checksum=10 <0x2f175680>
02 01/03/16 21:49:08.052 luup_log:237: ElkPlugin::handlerFunc Message type description: Keypad KeyChange Update <0x2f175680>
02 01/03/16 21:49:08.053 luup_log:237: ElkPlugin::setPartitionState: Set variable ‘ChimeEnabled’ = ‘0’ for partition 1 (device 244). <0x2f175680>
02 01/03/16 21:49:23.341 luup_log:237: ElkPlugin::checkMessage: length=22(0x16), message type=XK, data=‘1242211030116010’, misc=00, checksum=7D <0x2f175680>
02 01/03/16 21:49:23.342 luup_log:237: ElkPlugin::handlerFunc Message type description: Ethernet Module Test <0x2f175680>
02 01/03/16 21:49:36.471 luup_log:237: ElkPlugin::checkMessage: length=25(0x19), message type=KC, data=‘0100000000001111111’, misc=00, checksum=10 <0x2f175680>
02 01/03/16 21:49:36.472 luup_log:237: ElkPlugin::handlerFunc Message type description: Keypad KeyChange Update <0x2f175680>
02 01/03/16 21:49:36.473 luup_log:237: ElkPlugin::setPartitionState: Set variable ‘ChimeEnabled’ = ‘0’ for partition 1 (device 244). <0x2f175680>
02 01/03/16 21:49:53.371 luup_log:237: ElkPlugin::checkMessage: length=22(0x16), message type=XK, data=‘4242211030116010’, misc=00, checksum=7A <0x2f175680>
02 01/03/16 21:49:53.372 luup_log:237: ElkPlugin::handlerFunc Message type description: Ethernet Module Test <0x2f175680>
02 01/03/16 21:50:05.611 luup_log:237: ElkPlugin::checkMessage: length=25(0x19), message type=KC, data=‘0100000000001111111’, misc=00, checksum=10 <0x2f175680>
02 01/03/16 21:50:05.612 luup_log:237: ElkPlugin::handlerFunc Message type description: Keypad KeyChange Update <0x2f175680>
02 01/03/16 21:50:05.613 luup_log:237: ElkPlugin::setPartitionState: Set variable ‘ChimeEnabled’ = ‘0’ for partition 1 (device 244). <0x2f175680>
01 01/03/16 21:50:22.101 luup_log:237: ElkPlugin::getHeartbeat: OK 29 sec since last ping. <0x2e534680>
06 01/03/16 21:50:22.101 Device_Variable::m_szValue_set device: 237 service: urn:micasaverde-com:serviceId:ElkAlarmPanel1 variable: Heartbeat was: 29 now: 29 #hooks: 0 upnp: 0 skip: 0 v:(nil)/NONE duplicate:1 <0x2e534680>
02 01/03/16 21:50:23.381 luup_log:237: ElkPlugin::checkMessage: length=22(0x16), message type=XK, data=‘1243211030116010’, misc=00, checksum=7C <0x2f175680>
02 01/03/16 21:50:23.382 luup_log:237: ElkPlugin::handlerFunc Message type description: Ethernet Module Test <0x2f175680>
02 01/03/16 21:50:34.891 luup_log:237: ElkPlugin::checkMessage: length=25(0x19), message type=KC, data=‘0100000000001111111’, misc=00, checksum=10 <0x2f175680>
02 01/03/16 21:50:34.892 luup_log:237: ElkPlugin::handlerFunc Message type description: Keypad KeyChange Update <0x2f175680>
02 01/03/16 21:50:34.893 luup_log:237: ElkPlugin::setPartitionState: Set variable ‘ChimeEnabled’ = ‘0’ for partition 1 (device 244). <0x2f175680>
02 01/03/16 21:50:53.401 luup_log:237: ElkPlugin::checkMessage: length=22(0x16), message type=XK, data=‘4343211030116010’, misc=00, checksum=78 <0x2f175680>
02 01/03/16 21:50:53.402 luup_log:237: ElkPlugin::handlerFunc Message type description: Ethernet Module Test <0x2f175680>
02 01/03/16 21:51:04.001 luup_log:237: ElkPlugin::checkMessage: length=25(0x19), message type=KC, data=‘0100000000001111111’, misc=00, checksum=10 <0x2f175680>
02 01/03/16 21:51:04.002 luup_log:237: ElkPlugin::handlerFunc Message type description: Keypad KeyChange Update <0x2f175680>
02 01/03/16 21:51:04.003 luup_log:237: ElkPlugin::setPartitionState: Set variable ‘ChimeEnabled’ = ‘0’ for partition 1 (device 244). <0x2f175680>
02 01/03/16 21:51:23.421 luup_log:237: ElkPlugin::checkMessage: length=22(0x16), message type=XK, data=‘1244211030116010’, misc=00, checksum=7B <0x2f175680>
02 01/03/16 21:51:23.422 luup_log:237: ElkPlugin::handlerFunc Message type description: Ethernet Module Test <0x2f175680>
02 01/03/16 21:51:32.451 luup_log:237: ElkPlugin::checkMessage: length=25(0x19), message type=KC, data=‘0100000000001111111’, misc=00, checksum=10 <0x2f175680>
02 01/03/16 21:51:32.452 luup_log:237: ElkPlugin::handlerFunc Message type description: Keypad KeyChange Update <0x2f175680>
02 01/03/16 21:51:32.452 luup_log:237: ElkPlugin::setPartitionState: Set variable ‘ChimeEnabled’ = ‘0’ for partition 1 (device 244). <0x2f175680>
02 01/03/16 21:51:53.441 luup_log:237: ElkPlugin::checkMessage: length=22(0x16), message type=XK, data=‘4244211030116010’, misc=00, checksum=78 <0x2f175680>
02 01/03/16 21:51:53.442 luup_log:237: ElkPlugin::handlerFunc Message type description: Ethernet Module Test <0x2f175680>
02 01/03/16 21:52:01.581 luup_log:237: ElkPlugin::checkMessage: length=25(0x19), message type=KC, data=‘0100000000001111111’, misc=00, checksum=10 <0x2f175680>
02 01/03/16 21:52:01.582 luup_log:237: ElkPlugin::handlerFunc Message type description: Keypad KeyChange Update <0x2f175680>
02 01/03/16 21:52:01.583 luup_log:237: ElkPlugin::setPartitionState: Set variable ‘ChimeEnabled’ = ‘0’ for partition 1 (device 244). <0x2f175680>