Android version 2.5.9 still reporting Failed to parse JSON to custom endpoint

[TheQuickster]

I've just updated to 2.5.9 but I'm still getting the java error. This is to my self hosted site which returns an empty JSON string with a HTTP 200.

Is an empty JSON string and a HTTP 200 still a valid return or do I need to return some details in the JSON string.

I tried returning a command with the same result
{
"_type": "cmd",
"action": "clearWaypoints"
}

This is my own developed Python site but it has been working fine for years.

[ckrey]

As described in our booklet, an HTTP endpoint should return an array of JSON objects, which could be empty ([]).

In earlier versions we accepted zero length payloads and single commands ({"_type":...}) too as in your example above.

What do you mean with "returns an empty JSON string"?

[growse]

Can you elaborate on "Java Error"? Does it crash the process? Or does it just log a warning?

[thanasiskalos]

Hello

With version 2.5.9 there is again issue with traccar. Only Version 2.5.6 was working fine. On traccar server the message is being received and a status 200 is being returned by the http server but no location update is being processed. Seems that after the change to kotlinx serialization all the issues surfaced.

owntracks > XXX.XXX.XXX.XXX ] HTTP/1.1 200 OK\r\ncontent-length: 0\r\n\r\n

Debug Logs form the android App:

2026-05-18 08:59:13.706 E [DefaultDispatcher-worker-7] MessageProcessor$onMessageDeliveryFailed: Message delivery failed. queueLength: 20, message=[MessageLocation id=21aa64c1 ts=2026-05-18T05:53:04Z,lat=,long=,created_at=2026-05-18T05:53:05Z,trigger=DEFAULT]
2026-05-18 09:01:13.775 E [DefaultDispatcher-worker-1] HttpMessageProcessorEndpoint: HTTP Delivery failed
java.io.IOException: Failed to parse JSON
at org.owntracks.android.model.Parser.fromJson(SourceFile:21)
at org.owntracks.android.net.http.HttpMessageProcessorEndpoint.sendMessage-gIAlu-s(SourceFile:395)
at org.owntracks.android.services.MessageProcessor.sendAvailableMessages(SourceFile:557)
at org.owntracks.android.services.MessageProcessor.access$sendAvailableMessages(SourceFile:1)
at org.owntracks.android.services.MessageProcessor$sendAvailableMessages$1.invokeSuspend(Unknown Source:11)
at kotlin.coroutines.jvm.internal.BaseContinuationImpl.resumeWith(SourceFile:9)
at kotlinx.coroutines.UndispatchedCoroutine.afterResume(SourceFile:54)
at kotlinx.coroutines.AbstractCoroutine.resumeWith(SourceFile:23)
at kotlin.coroutines.jvm.internal.BaseContinuationImpl.resumeWith(SourceFile:32)
at kotlinx.coroutines.DispatchedTask.run(SourceFile:109)
at androidx.work.Worker$2.run(SourceFile:150)
at kotlinx.coroutines.scheduling.TaskImpl.run(SourceFile:3)
at kotlinx.coroutines.scheduling.CoroutineScheduler$Worker.run(SourceFile:93)
Caused by: kotlinx.serialization.json.internal.JsonDecodingException: Cannot read Json element because of unexpected end of the input at path: $
JSON input:
at kotlinx.serialization.json.internal.WriteModeKt.JsonDecodingException(SourceFile:3)
at kotlinx.serialization.json.internal.WriteModeKt.JsonDecodingException(SourceFile:4)
at androidx.room.RoomOpenHelper.fail(SourceFile:61)
at androidx.room.RoomOpenHelper.fail$default(SourceFile:13)
at org.bouncycastle.crypto.engines.RC532Engine.read(SourceFile:227)
at kotlinx.serialization.json.internal.StreamingJsonDecoder.decodeJsonElement(SourceFile:12)
at kotlinx.serialization.json.internal.WriteModeKt.decodeSerializableValuePolymorphic(SourceFile:28)
at kotlinx.serialization.json.internal.StreamingJsonDecoder.decodeSerializableValue$1(SourceFile:35)
at kotlinx.serialization.json.Json.decodeFromString(SourceFile:26)
at org.owntracks.android.model.Parser.fromJson(SourceFile:19)
... 12 more

2026-05-18 09:01:13.777 W [DefaultDispatcher-worker-1] MessageProcessor: Error sending message [MessageLocation id=21aa64c1 ts=2026-05-18T05:53:04Z,,created_at=2026-05-18T05:53:05Z,trigger=DEFAULT]. Re-queueing
org.owntracks.android.net.MessageProcessorEndpoint$OutgoingMessageSendingException: java.io.IOException: Failed to parse JSON
at org.owntracks.android.net.http.HttpMessageProcessorEndpoint.sendMessage-gIAlu-s(SourceFile:465)
at org.owntracks.android.services.MessageProcessor.sendAvailableMessages(SourceFile:557)
at org.owntracks.android.services.MessageProcessor.access$sendAvailableMessages(SourceFile:1)
at org.owntracks.android.services.MessageProcessor$sendAvailableMessages$1.invokeSuspend(Unknown Source:11)
at kotlin.coroutines.jvm.internal.BaseContinuationImpl.resumeWith(SourceFile:9)
at kotlinx.coroutines.UndispatchedCoroutine.afterResume(SourceFile:54)
at kotlinx.coroutines.AbstractCoroutine.resumeWith(SourceFile:23)
at kotlin.coroutines.jvm.internal.BaseContinuationImpl.resumeWith(SourceFile:32)
at kotlinx.coroutines.DispatchedTask.run(SourceFile:109)
at androidx.work.Worker$2.run(SourceFile:150)
at kotlinx.coroutines.scheduling.TaskImpl.run(SourceFile:3)
at kotlinx.coroutines.scheduling.CoroutineScheduler$Worker.run(SourceFile:93)
Caused by: java.io.IOException: Failed to parse JSON
at org.owntracks.android.model.Parser.fromJson(SourceFile:21)
at org.owntracks.android.net.http.HttpMessageProcessorEndpoint.sendMessage-gIAlu-s(SourceFile:395)
... 11 more
Caused by: kotlinx.serialization.json.internal.JsonDecodingException: Cannot read Json element because of unexpected end of the input at path: $
JSON input:
at kotlinx.serialization.json.internal.WriteModeKt.JsonDecodingException(SourceFile:3)
at kotlinx.serialization.json.internal.WriteModeKt.JsonDecodingException(SourceFile:4)
at androidx.room.RoomOpenHelper.fail(SourceFile:61)
at androidx.room.RoomOpenHelper.fail$default(SourceFile:13)
at org.bouncycastle.crypto.engines.RC532Engine.read(SourceFile:227)
at kotlinx.serialization.json.internal.StreamingJsonDecoder.decodeJsonElement(SourceFile:12)
at kotlinx.serialization.json.internal.WriteModeKt.decodeSerializableValuePolymorphic(SourceFile:28)
at kotlinx.serialization.json.internal.StreamingJsonDecoder.decodeSerializableValue$1(SourceFile:35)
at kotlinx.serialization.json.Json.decodeFromString(SourceFile:26)
at org.owntracks.android.model.Parser.fromJson(SourceFile:19)
... 12 more

2026-05-18 09:01:13.779 E [DefaultDispatcher-worker-6] MessageProcessor$onMessageDeliveryFailed: Message delivery failed. queueLength: 20, message=[MessageLocation id=21aa64c1 ts=2026-05-18T05:53:04Z,,created_at=2026-05-18T05:53:05Z,trigger=DEFAULT]

Best Regards

[growse]

owntracks > XXX.XXX.XXX.XXX ] HTTP/1.1 200 OK\r\ncontent-length: 0\r\n\r\n

You're returning a completely empty response to the location POST?

[thanasiskalos]

Hello
This is the whole message Owntrack returns to Traccar . Android app STATUS reads: java.io.IOExemption: Failed to parse JSON.

Traccar log: ( all sensitive info have been removed)
2026-05-18 09:59:58 INFO: [Te8b4: owntracks < xx.xx.xx.xx] POST / HTTP/1.1\r\nUser-Agent: Owntracks-Android/gms/42050r\nX-Limit-D: xxxxx\r\nContent-Type: application/json; charset=utf-8\r\nContent-Length: 339\r\nHost: \r\nConnection: Keep-Alive\r\nAccept-Encoding: gzip\r\n\r\n{"_type":"location","topic":"owntracks/user/xxxx","qos":1,"retained":true,"created_at":13585,"_id":"","source":"fused","batt":40,"bs":1,"acc":10,"vac":1,"lat":xxx,"lon":xxx,"alt":12,"vel":1,"cog":324,"tst":184,"m":1,"conn":"w","inregions":[],"BSSID":"","SSID":"","tid":"xx"}
2026-05-18 09:59:58 INFO: [Te8b48673: owntracks > xxx.xxx.xxx.xxx] HTTP/1.1 200 OK\r\ncontent-length: 0\r\n\r\n
2026-05-18 10:04:06 INFO: [Te8b48673] id: xx, time: 2026-05-18 08:53:04, lat: xxx lon: xx, speed: 0.5, course: 324.0, accuracy: 10.

Notice that on the last message the time has not been updated to the current time of the android mobile.

By the way I tried the F-Droid 2.5.7 version and same issues and errors are reported.

Regards

[ckrey]

owntracks > XXX.XXX.XXX.XXX ] HTTP/1.1 200 OK\r\ncontent-length: 0\r\n\r\n

You're returning a completely empty response to the location POST?

@growse, yes this is what traccar does: return no content.
What is the actual problem? As far as I can see

• traccar processes the message
• the Android app accepts the HTTP 200 as processed
• the Android app tries to parse the zero length message, fails to do so and logs the problem.

[michaelb26]

Hi All also having this issue seems to be with the new Android update, iphone still seems to be working and help?

[thanasiskalos]

owntracks > XXX.XXX.XXX.XXX ] HTTP/1.1 200 OK\r\ncontent-length: 0\r\n\r\n

You're returning a completely empty response to the location POST?

@growse, yes this is what traccar does: return no content. What is the actual problem? As far as I can see

• traccar processes the message
• the Android app accepts the HTTP 200 as processed
• the Android app tries to parse the zero length message, fails to do so and logs the problem.

If you need more debugs let me know. But as said with version 2.5.6 all worked fine. I dont know if other servers - like Dawarich- have issue , but with version 2.5.7 / 2.5.8 they reported that they also had.

[TheQuickster]

Can you elaborate on "Java Error"? Does it crash the process? Or does it just log a warning?

It's the "Failed to Parse JSON" error, regardless of what I return.

[thanasiskalos]

Hello

More logs with Debug enabled from owntracks app android v 2.5.8 from F-Droid. . Hope it helps more.
I get the "Failed to Parse JSON" right after the connection to traccar server .The traccar server is not updated with new android location.
Is this issue affects only traccar server ?

Regards

2026-05-20 09:12:51.086 I [main] BaseApp: Historical process exited at 2026-05-20T06:12:45.216Z. reason: null, status: 9, reason: 2
2026-05-20 09:12:51.178 I [DefaultDispatcher-worker-1] WaypointsRepo: Migrating waypoints from legacy storage
2026-05-20 09:12:51.180 D [DefaultDispatcher-worker-1] WaypointsRepo: Setting migration complete idlingresource
2026-05-20 09:12:51.203 D [DefaultDispatcher-worker-2] RoomBackedMessageQueue$initialize: Initialized RoomBackedMessageQueue with 430 messages
2026-05-20 09:12:51.203 D [DefaultDispatcher-worker-2] RoomBackedMessageQueue: No legacy storage found, skipping migration
2026-05-20 09:12:51.205 D [DefaultDispatcher-worker-2] MessageProcessor$queueInitJob: Initialized outgoingQueue with size: 430
2026-05-20 09:12:51.349 I [main] GeocoderProvider: Setting geocoding provider to None
2026-05-20 09:12:51.355 D [main] ServiceStarter$Impl: requesting service start with action null
2026-05-20 09:12:51.374 D [main] MapActivity: Got a rotation vector sensor
2026-05-20 09:12:51.457 D [main] MapViewModel: setting view mode: VIEW_DEVICE
2026-05-20 09:12:51.457 W [main] MapViewModel: no location available
2026-05-20 09:12:51.459 D [main] OSMMapFragment: OSMMapFragment initMap locationEnabled=true
2026-05-20 09:12:51.469 D [main] MapActivity: Checking and requesting notification permissions
2026-05-20 09:12:51.469 D [main] MapActivity: Checking and requesting location permissions
2026-05-20 09:12:51.470 D [main] MapActivity: Checking and requesting background location permissions
2026-05-20 09:12:51.470 D [main] PreferencesStore: Setting preference userDeclinedEnableBackgroundLocationPermissions to true (coerced to true)
2026-05-20 09:12:51.470 D [main] MapActivity: Check and request location services
2026-05-20 09:12:51.470 D [main] MapActivity: Location services enabled
2026-05-20 09:12:51.596 I [main] BackgroundService: Permissions. ACCESS_BACKGROUND_LOCATION: true
2026-05-20 09:12:51.598 I [main] BackgroundService: Permissions. ACCESS_COARSE_LOCATION: true
2026-05-20 09:12:51.598 I [main] BackgroundService: Permissions. ACCESS_FINE_LOCATION: true
2026-05-20 09:12:51.601 I [main] AospLocationProviderClient: Using AOSP as a location provider. Available providers are [passive, network, fused, gps]
2026-05-20 09:12:51.606 D [main] BackgroundService$PowerStateLogger: triggeringAction=serviceOnCreate isPowerSaveMode=false locationPowerSaveMode=0 isDeviceIdleMode=false isInteractive=true isIgnoringBatteryOptimizations=true
2026-05-20 09:12:51.608 D [main] BackgroundService: no intent or action provided, setting up location request and scheduling location ping.
2026-05-20 09:12:51.632 I [main] PreferencesStore: Setting default preference value for locatorPriority to null
2026-05-20 09:12:51.632 D [main] PreferencesStore: Setting preference locatorPriority to null (coerced to null)
2026-05-20 09:12:51.632 D [main] BackgroundService: location update request params: LocationRequest(fastestInterval=PT1S, smallestDisplacement=500.0, numUpdates=null, expirationDuration=null, priority=BalancedPowerAccuracy, interval=PT1M, waitForAccurateLocation=null)
2026-05-20 09:12:51.633 W [main] AospLocationProviderClient: No current location updates found for Backgroundservice callback[DEFAULT]
2026-05-20 09:12:51.637 D [backgroundHandlerThread] BackgroundService$LocationCallbackWithReportType: Location result received: LocationResult(lastLocation=Location[fused hAcc=100.0 et=+53d8h12m15s79ms alt=125.5 vAcc=43.049])
2026-05-20 09:12:51.641 D [main] Scheduler: WorkManager queue task PERIODIC_TASK_SEND_LOCATION_PING as 0c7c-259fc90b1d4b with interval 15 minutes
2026-05-20 09:12:51.641 D [main] SignificantMotionSensor: Significant motion sensor disabled (experimental feature not enabled)
2026-05-20 09:12:51.641 D [main] MessageProcessor: Initializing MessageProcessor
2026-05-20 09:12:51.646 D [DefaultDispatcher-worker-4] MessageProcessor: Reloading outgoing message processor
2026-05-20 09:12:51.646 D [DefaultDispatcher-worker-4] MessageProcessor: Destroying previous endpoint
2026-05-20 09:12:51.647 I [DefaultDispatcher-worker-5] BackgroundService$setupGeofences: Setting up geofences for 0 waypoints
2026-05-20 09:12:51.649 D [backgroundHandlerThread] BackgroundService$LocationCallbackWithReportType: Location result received: LocationResult(lastLocation=Location[network XXXXX hAcc=100.0 et=+53d8h13m3s809ms alt=125.5 vAcc=60.104496])
2026-05-20 09:12:51.650 D [backgroundHandlerThread] BackgroundService$LocationCallbackWithReportType: Location result received: LocationResult(lastLocation=Location[network XXXXX hAcc=100.0 et=+53d8h13m09ms alt=125.5 vAcc=6496])
2026-05-20 09:12:51.664 D [main] BackgroundService: Background service bound intent=Intent { cmp=org.owntracks.android/.services.BackgroundService }
2026-05-20 09:12:51.697 D [main] LocationProcessor: publishLocationMessage for Location[fused XXXXX hAcc=100.0 et=+53d8h115s79ms alt=125.5 vAcc=43.049] triggered by DEFAULT
2026-05-20 09:12:51.698 D [main] LocationProcessor: Checking if location triggers waypoint transitions. waypoints: [], trigger=DEFAULT, fusedRegionDetection: true
2026-05-20 09:12:51.703 D [DefaultDispatcher-worker-5] MessageProcessor$queueMessageForSending: Queueing message=[MessageLocation id=9013d343 ts=2026-05-20T06:12:02Z,,created_at=2026-05-20T06:12:51.698Z,trigger=DEFAULT], current queueLength:430
2026-05-20 09:12:51.712 D [main] MapActivity$serviceConnection: MapActivity connected to service
2026-05-20 09:12:51.713 D [DefaultDispatcher-worker-5] RoomBackedMessageQueue: Enqueued message with sequence 1832
2026-05-20 09:12:51.713 D [main] MessageProcessor$serviceConnection: MessageProcessor has connected to ComponentInfo{org.owntracks.android/org.owntracks.android.services.BackgroundService}
2026-05-20 09:12:51.724 D [main] LocationProcessor: publishLocationMessage for Location[network XXXXX hAcc=100.0 et=+53d8h13mms alt=125.5 vAcc=60.104496] triggered by DEFAULT
2026-05-20 09:12:51.725 D [main] LocationProcessor: Checking if location triggers waypoint transitions. waypoints: [], trigger=DEFAULT, fusedRegionDetection: true
2026-05-20 09:12:51.730 D [main] LocationProcessor: publishLocationMessage for Location[network XXXXX hAcc=100.0 et=+53d8h13m3ms alt=125.5 vAcc=60.104496] triggered by DEFAULT
2026-05-20 09:12:51.730 D [DefaultDispatcher-worker-4] MessageProcessor$queueMessageForSending: Queueing message=[MessageLocation id=807c4e2b ts=2026-05-20T06:12:51Z,XXXXX,created_at=2026-05-20T06:12:51.725Z,trigger=DEFAULT], current queueLength:431
2026-05-20 09:12:51.730 D [main] LocationProcessor: Checking if location triggers waypoint transitions. waypoints: [], trigger=DEFAULT, fusedRegionDetection: true
2026-05-20 09:12:51.735 D [DefaultDispatcher-worker-5] SendLocationPingWorker: SendLocationPingWorker started
2026-05-20 09:12:51.737 D [DefaultDispatcher-worker-4] RoomBackedMessageQueue: Enqueued message with sequence 1833
2026-05-20 09:12:51.740 D [DefaultDispatcher-worker-4] MessageProcessor$queueMessageForSending: Queueing message=[MessageLocation id=ccff2657 ts=2026-05-20T06:12:51Z,XXXXX,created_at=2026-05-20T06:12:51.731Z,trigger=DEFAULT], current queueLength:432
2026-05-20 09:12:51.746 D [DefaultDispatcher-worker-2] RoomBackedMessageQueue: Enqueued message with sequence 1834
2026-05-20 09:12:51.756 D [main] SendLocationPingWorker$doWork$serviceConnection: SendLocationPingWorker has connected to ComponentInfo{org.owntracks.android/org.owntracks.android.services.BackgroundService}
2026-05-20 09:12:51.758 D [DefaultDispatcher-worker-5] LocationProcessor: publishLocationMessage for Location[network XXXXX hAcc=100.0 et=+53d8h13m3s809ms alt=125.5 vAcc=60.104496] triggered by PING
2026-05-20 09:12:51.759 D [DefaultDispatcher-worker-5] LocationProcessor: Checking if location triggers waypoint transitions. waypoints: [], trigger=PING, fusedRegionDetection: true
2026-05-20 09:12:51.782 D [DefaultDispatcher-worker-4] MessageProcessor$queueMessageForSending: Queueing message=[MessageLocation id=a0ab3db4 ts=2026-05-20T06:12:51Z,XXXXX,created_at=2026-05-20T06:12:51.759Z,trigger=PING], current queueLength:433
2026-05-20 09:12:51.790 D [DefaultDispatcher-worker-5] RoomBackedMessageQueue: Enqueued message with sequence 1835
2026-05-20 09:12:51.857 D [DefaultDispatcher-worker-1] MessageProcessor: Starting outbound message loop.
2026-05-20 09:12:51.867 D [DefaultDispatcher-worker-1] RoomBackedMessageQueue$dequeue: Dequeued message with id 1820
2026-05-20 09:12:51.867 D [DefaultDispatcher-worker-1] MessageProcessor: Taken message off queue: [MessageLocation id=5bfa4 ts=2026-05-18T07:47:32Z,,created_at=2026-05-18T07:48:21Z,trigger=PING]
2026-05-20 09:12:51.871 D [DefaultDispatcher-worker-1] HttpMessageProcessorEndpoint: Publishing Message JSON {"_type":"location","topic":"owntracks/user/XXXXX","qos":1,"retained":true,"created_at":1770501,"_id":"502b4","source":"fused","t":"p","batt":95,"bs":1,"acc":100,"vac":29,"lat":,"lon":,"alt":162,"tst":1779090452,"m":1,"conn":"m","inregions":[],"tid":"XXXXX"}
2026-05-20 09:12:52.104 D [DefaultDispatcher-worker-1] HttpMessageProcessorEndpoint: HTTP response received: Response{protocol=http/1.1, code=200, message=OK, url=http://xxxxxxx/}
2026-05-20 09:12:52.105 D [DefaultDispatcher-worker-1] HttpMessageProcessorEndpoint: HTTP response body:
2026-05-20 09:12:52.106 E [DefaultDispatcher-worker-1] HttpMessageProcessorEndpoint: HTTP Delivery failed
java.io.IOException: Failed to parse JSON
at org.owntracks.android.model.Parser.fromJson(SourceFile:19)
at org.owntracks.android.net.http.HttpMessageProcessorEndpoint.sendMessage-gIAlu-s(SourceFile:395)
at org.owntracks.android.services.MessageProcessor.sendAvailableMessages(SourceFile:557)
at org.owntracks.android.services.MessageProcessor.access$sendAvailableMessages(SourceFile:1)
at org.owntracks.android.services.MessageProcessor$sendAvailableMessages$1.invokeSuspend(Unknown Source:11)
at kotlin.coroutines.jvm.internal.BaseContinuationImpl.resumeWith(SourceFile:9)
at kotlinx.coroutines.UndispatchedCoroutine.afterResume(SourceFile:54)
at kotlinx.coroutines.AbstractCoroutine.resumeWith(SourceFile:23)
at kotlin.coroutines.jvm.internal.BaseContinuationImpl.resumeWith(SourceFile:32)
at kotlinx.coroutines.DispatchedTask.run(SourceFile:109)
at androidx.work.Worker$2.run(SourceFile:150)
at kotlinx.coroutines.scheduling.TaskImpl.run(SourceFile:3)
at kotlinx.coroutines.scheduling.CoroutineScheduler$Worker.run(SourceFile:93)
Caused by: kotlinx.serialization.json.internal.JsonDecodingException: Cannot read Json element because of unexpected end of the input at path: $
JSON input:
at kotlinx.serialization.json.internal.WriteModeKt.JsonDecodingException(SourceFile:3)
at kotlinx.serialization.json.internal.WriteModeKt.JsonDecodingException(SourceFile:4)
at androidx.room.RoomOpenHelper.fail(SourceFile:61)
at androidx.room.RoomOpenHelper.fail$default(SourceFile:13)
at org.bouncycastle.crypto.engines.RC532Engine.read(SourceFile:227)
at kotlinx.serialization.json.internal.StreamingJsonDecoder.decodeJsonElement(SourceFile:12)
at kotlinx.serialization.json.internal.WriteModeKt.decodeSerializableValuePolymorphic(SourceFile:28)
at kotlinx.serialization.json.internal.StreamingJsonDecoder.decodeSerializableValue$1(SourceFile:35)
at kotlinx.serialization.json.Json.decodeFromString(SourceFile:26)
at org.owntracks.android.model.Parser.fromJson(SourceFile:17)
... 12 more

2026-05-20 09:12:52.109 W [DefaultDispatcher-worker-1] MessageProcessor: Error sending message [MessageLocation id=5bfa02b4 ts=2026-05-18T07:47:32Z,lat=XXXXX,long=XXXXX,created_at=2026-05-18T07:48:21Z,trigger=PING]. Re-queueing
org.owntracks.android.net.MessageProcessorEndpoint$OutgoingMessageSendingException: java.io.IOException: Failed to parse JSON
at org.owntracks.android.net.http.HttpMessageProcessorEndpoint.sendMessage-gIAlu-s(SourceFile:465)
at org.owntracks.android.services.MessageProcessor.sendAvailableMessages(SourceFile:557)
at org.owntracks.android.services.MessageProcessor.access$sendAvailableMessages(SourceFile:1)
at org.owntracks.android.services.MessageProcessor$sendAvailableMessages$1.invokeSuspend(Unknown Source:11)
at kotlin.coroutines.jvm.internal.BaseContinuationImpl.resumeWith(SourceFile:9)
at kotlinx.coroutines.UndispatchedCoroutine.afterResume(SourceFile:54)
at kotlinx.coroutines.AbstractCoroutine.resumeWith(SourceFile:23)
at kotlin.coroutines.jvm.internal.BaseContinuationImpl.resumeWith(SourceFile:32)
at kotlinx.coroutines.DispatchedTask.run(SourceFile:109)
at androidx.work.Worker$2.run(SourceFile:150)
at kotlinx.coroutines.scheduling.TaskImpl.run(SourceFile:3)
at kotlinx.coroutines.scheduling.CoroutineScheduler$Worker.run(SourceFile:93)
Caused by: java.io.IOException: Failed to parse JSON
at org.owntracks.android.model.Parser.fromJson(SourceFile:19)
at org.owntracks.android.net.http.HttpMessageProcessorEndpoint.sendMessage-gIAlu-s(SourceFile:395)
... 11 more
Caused by: kotlinx.serialization.json.internal.JsonDecodingException: Cannot read Json element because of unexpected end of the input at path: $
JSON input:
at kotlinx.serialization.json.internal.WriteModeKt.JsonDecodingException(SourceFile:3)
at kotlinx.serialization.json.internal.WriteModeKt.JsonDecodingException(SourceFile:4)
at androidx.room.RoomOpenHelper.fail(SourceFile:61)
at androidx.room.RoomOpenHelper.fail$default(SourceFile:13)
at org.bouncycastle.crypto.engines.RC532Engine.read(SourceFile:227)
at kotlinx.serialization.json.internal.StreamingJsonDecoder.decodeJsonElement(SourceFile:12)
at kotlinx.serialization.json.internal.WriteModeKt.decodeSerializableValuePolymorphic(SourceFile:28)
at kotlinx.serialization.json.internal.StreamingJsonDecoder.decodeSerializableValue$1(SourceFile:35)
at kotlinx.serialization.json.Json.decodeFromString(SourceFile:26)
at org.owntracks.android.model.Parser.fromJson(SourceFile:17)
... 12 more

[sjcliffe]

I'm using Owntracks on Android with openHAB and its GPSTracker binding. Three days ago it stopped receiving updates from my phone and after a bit of digging I came across this issue.

I installed Owntracks from the Play store and confirmed that I have 2.5.9 so I uninstalled it and manually installed the 2.5.6 apk release. I'm now getting updates again so this issue is not just isolated to traccar.

[yndtrud]

Same openHAB issue with latest Google Play version. v2.5.6 works, 2.5.7+ with error