Hello,

I'm fighting an issue in my mqtt client for last three weeks. I'm using PubSubClient library. It all runs on esp12f module with 2.5.0 release.

The behaviour is strange, my mqtt connection timeouts and it depends on lwip version. No error, no crash, just socket timeout. I'm not using delays, except one 10ms in loop, to allow cpu to sleep at idle task (light sleep).

I've tried lwip2 higher bandwidth/lower memory/ipv6 and it does not matter, connection timeouts few times per hour.

When switched to lwip 1.4 higher bandwidth, it timeouts only once a day, but still.

WiFi connection is not being lost. Router seems to be connected without interruptions.

Tried earlier releases, same results.