UPDATE: before I just hit submit, I did a fifth reboot and it seems to work now. Since I’ve already documented the issue, thought I might as well share it in case someone else has a similar issue, or someone might recognize the bug and fix it “in advance” 
If not, please delete the thread.
Hi,
I have updated to OH2.2 via openhabian, and ikea binding got updated as well. My remotes appeared into the inbox and I’ve added them fine. All was good. Then I restarted ikea gateway, and now no item (except gateway itself) is initialized. I also saw this in the logs
==> /var/log/openhab2/openhab.log <==
2017-12-31 13:33:02.774 [WARN ] [iscovery.TradfriDiscoveryParticipant] - Discovered Tradfri gateway doesn’t have an IP address: [ServiceInfoImpl@260655871 name: ‘gw-dcefcaba51d5._coap._udp.local.’ address: ‘(null):0’ status: ‘DNS: JmDNS-IP-1 [/192.168.1.30] state: probing 1 task: null’, has NO data, empty]
all tradfri things have “Status: UNINITIALIZED - HANDLER_INITIALIZING_ERROR”
I noticed that my secret key on the gateway was empty (usually it should be *******) so I entered it again, and it didn’t help, this did appear in the logs
2017-12-31 13:45:00.262 [hingStatusInfoChangedEvent] - ‘tradfri:gateway:gwdcefcaba51d5’ changed from ONLINE to UNKNOWN
==> /var/log/openhab2/openhab.log <==
2017-12-31 13:45:00.430 [INFO ] [radfri.handler.TradfriGatewayHandler] - Received pre-shared key for gateway ‘192.168.1.102’
==> /var/log/openhab2/events.log <==
2017-12-31 13:45:00.482 [me.event.ThingUpdatedEvent] - Thing ‘tradfri:gateway:gwdcefcaba51d5’ has been updated.
2017-12-31 13:45:03.297 [hingStatusInfoChangedEvent] - ‘tradfri:gateway:gwdcefcaba51d5’ changed from UNKNOWN to ONLINE
but again, all things are uninitialized.
Tradfri works from its own app, restarting both openhab and gateway didn’t help
I’ve also noticed this in the logs, not sure if it is related
2017-12-31 13:53:57.041 [WARN ] [.internal.proxy.BlockingProxyServlet] - Proxy servlet failed to stream content due to a timeout
2017-12-31 13:54:00.039 [WARN ] [.internal.proxy.BlockingProxyServlet] - Proxy servlet failed to stream content due to a timeout
2017-12-31 13:54:02.039 [WARN ] [.internal.proxy.BlockingProxyServlet] - Proxy servlet failed to stream content due to a timeout
2017-12-31 13:54:02.042 [WARN ] [.internal.proxy.BlockingProxyServlet] - Proxy servlet failed to stream content: java.net.SocketTimeoutException: Connect Timeout
2017-12-31 13:54:02.044 [WARN ] [.internal.proxy.BlockingProxyServlet] - Proxy servlet failed to stream content: java.net.SocketTimeoutException: Connect Timeout
2017-12-31 13:54:02.047 [WARN ] [.internal.proxy.BlockingProxyServlet] - Proxy servlet failed to stream content: java.net.SocketTimeoutException: Connect Timeout