The most important changes in this release is that ESP8266 boards are supported now. A few compiler preprocessor directives (#if defined()) are used to add a few yield()-statements for the ESP8266 only. Also, the final StaticJsonDocument is replaced by a DynamicJsonDocument because the ESP8266's stack is not big enough for the static variant.
The Advanced_Thermostat.ino program uses the PubSubClient again as MQTT client. I found a work around for the connection losses by managing the TCP/IP connection form the program and not from the library. This may imply that you have to add the PubSubClient-library using the library manager (search for 'pubsubclient oleary')
The README.md's are extended and a few typo's are removed.
The comments at the head of the examples are adapted.
A few small bugs were solved.
Full Changelog: v1.1.0...v1.2.0