2.5.0: Issues with Arduino API

[d-a-v]

UDP virtual IPAddress remoteIP() =0; virtual IPAddress remoteIP() const =0;
you can't change a virtual function in an established Arduino core class

5c4db3a#commitcomment-32254962

other networking libraries Client implementations do not implement flush and stop with parameter.
"The type 'UIPClient' must implement the inherited pure virtual method 'Client::stop' "

83a8076#commitcomment-32254941

@JAndrassy Can you please give more details ?

Also If your sketch does not compile and returns error needs to be addressed.

[JAndrassy]

There are other networking libraries used with esp8266, not only the native WiFi or bundled Ethernet library (why is it there?). If you change the virtual functions of the Arduino networking base classes Client, Server, UDP the libraries don't compile. Function flush with parameter is a different virtual function then flush without parameter. The default value of the parameter doesn't change it. So now for example the UIPEthernet library or the standard Ethernet library and perhaps some GPRS libraries don't compile for esp8266 because they don't implement flush, stop, remoteIP with a parameter.

UIPEthernet/UIPEthernet#49

To Ethernet library: The official Arduino Ethernet library was upgraded last year to 2.0.0 by Paul Stoffregen to support Wiznet 5200 and 5500. He tested it with esp8266. The Ethernet library bundled in esp8266 core package supports only W5100.

[d-a-v]

It will be addressed for next release 2.5.1

[PaulStoffregen]

FWIW, there was an unresolved problem with DNS lookups by the Ethernet lib. Only ESP8266 has this problem. The exact same code ran perfectly on all other boards, including ESP32. I never did a deeper investigation into why that failed on ESP8266. Maybe someday....

If anyone cares about Wiznet-based Ethernet on ESP8266, please test some of the library's examples which use a text-based hostname rather than only IP numbers.

[JAndrassy]

recommended
https://github.com/arduino/ArduinoCore-API