docs_api_note (espressif#9128)

Author: VojtechBartoska

README.md

@@ -36,6 +36,10 @@ You can use the [Arduino-ESP32 Online Documentation](https://docs.espressif.com/
 
 ---
 
+**APIs compatibility with ESP8266 and Arduino-CORE (Arduino.cc) is explained [here](https://docs.espressif.com/projects/arduino-esp32/en/latest/libraries.html#apis).**
+
+---
+
 * [Getting Started](https://docs.espressif.com/projects/arduino-esp32/en/latest/getting_started.html)
 * [Installing (Windows, Linux and macOS)](https://docs.espressif.com/projects/arduino-esp32/en/latest/installing.html)
 * [Libraries](https://docs.espressif.com/projects/arduino-esp32/en/latest/libraries.html)

docs/en/libraries.rst

@@ -71,6 +71,11 @@ APIs
 
 The Arduino ESP32 offers some unique APIs, described in this section:
 
+.. note:: 
+    Please be advised that we cannot ensure continuous compatibility between the Arduino Core ESP32 APIs and ESP8266 APIs, as well as Arduino-Core APIs (Arduino.cc).
+    While our aim is to maintain harmony, the addition of new features may result in occasional divergence. We strive to achieve the best possible integration but acknowledge
+    that perfect compatibility might not always be feasible. Please refer to the documentation for any specific considerations.
+
 .. toctree::
     :maxdepth: 1
     :glob: