@hilbrand, I noticed just now when updating to the August 2019 beta of the TP-Link binding that the Signal channel is no longer working, and is generating a warning in the log:
2019-11-15 22:24:02.742 [WARN ] [mmon.WrappedScheduledExecutorService] - Scheduled runnable ended with an exception: java.lang.NoSuchFieldError: DECIBEL_MILLIWATTS
at org.openhab.binding.tplinksmarthome.internal.handler.SmartHomeHandler.updateChannelState(SmartHomeHandler.java:254) ~[?:?]
at org.openhab.binding.tplinksmarthome.internal.handler.SmartHomeHandler.lambda$3(SmartHomeHandler.java:234) ~[?:?]
at java.util.ArrayList.forEach(ArrayList.java:1257) ~[?:?]
at java.util.Collections$UnmodifiableCollection.forEach(Collections.java:1080) ~[?:?]
at org.openhab.binding.tplinksmarthome.internal.handler.SmartHomeHandler.refreshChannels(SmartHomeHandler.java:234) ~[?:?]
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) ~[?:?]
at java.util.concurrent.FutureTask.runAndReset(FutureTask.java:308) ~[?:?]
at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$301(ScheduledThreadPoolExecutor.java:180) ~[?:?]
at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:294) ~[?:?]
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) [?:?]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) [?:?]
at java.lang.Thread.run(Thread.java:748) [?:?]
I noticed before updating to the latest build that signal strengths weren’t showing up in PaperUI, but didn’t give it any thought. My guess is that TP-Link changed the “DECIBEL_MILLIWATTS” field to a different name in a recent firmware update.