New ESP8266 Arduino core version 3.0.0

There is a new major release of the ESP8266 core, taking the latest version from 2.7.4 to 3.0.0

There’s a long list of changes, some of which seem quite minor and some that are significant changes. There seems to be a major change to the way that memory is handled, and a number of changes to the WiFi code as well.



Is it safe to change? :man_facepalming: Some builds ruin more than they fix.

I’ve upgraded, but most of my coding since has been for the ESP32, so haven’t given it much use.
Not seen any issues so far.



The new ESP8266 core v3.0.0 introduces many breaking changes. You even can’t compile your code in certain cases.

The most important breaking changes, which can affect everybody, are in

  1. WiFi : especially when you’re using AP mode, with custom AP IP (such as, not the standard
  2. SSL: The total deletion of deprecated axTLS will cause the ESP8266 SSL-related Blynk code not compiled. You have to drastically change the code to use BearSSL and update CA Certs. For Blynk cloud server, you can use inSecured mode.
  3. ISR-related code: To use IRAM_ATTR in place of ICACHE_RAM_ATTR

See the whole list in Pete’s post #1 or here

Check Blynk_WM Library to see how to fix code to enable it to compile using both ESP8266 core v2.7.4- and v3.0.0+