Hi Matt.
 
Try updating your ESP8266 boards version. Go to Tools > Boards > Boards Manager, search for ESP8266, and updated to the latest version 3.0.2.
Then, restart your Arduino IDE and try to compile the code again.
 
Let me know if this solves your issue.
 
Regards,
Sara

Hi Sara,
Thanks for getting back to me so quickly. I did as you suggested and found I was already running 3.0.2, so I backed up to 3.0.1, restarted IDE , and the code complied.
Then I went back and upgraded to 3.0.2 again, restarted IDE and coded compiled and uploaded successfully .
Looks to me as though my original installation of 3.0.2 was flawed.
Thanks so much for your help, now back to learning.
Cheers,
Matt

Great!
I’m glad the issue is solved.
I’ll mark this issue as resolved. If you need further help, you just need to open a new question in our forum.
Regards,
Sara

I’m just interesting with mqtt and grab out from my library Smart_Home_Raspberry_Pi_ESP32_ESP8266 (V1_3).
As seen, after some other library installed as AsyncMQTTclient, which is now called AsyncMQTT_Generic, I’ve got issue with Ticker. See history here after.
I’ve dowloaded it directly with library toolbar (IDE 2.3.x) and the last version is 4.4.
Compilation has been down, and returns no error (except mine at the begining). But regarding console, I’ve seen that Ticker v1.0 has been chosen by the system instead of the last one.
Whatever I decide to remove the oldest (hopefully located in the original folder of Arduino’s Library, not my current one).
Then new compilation returns error of function mismatch.
So I grab information on library keyword and can confirm functions are totally different.
In fact it exists two different library the original written by Ivan Grokhtokov <ivan@esp8266.com> (library.properties) and the last one from Stephan Staub (find with Github link) which is probably richest but with completely different keywords.
I decided to downgrade v4.4 to 3.2 (the oldest purposed) but it doesn’t work neither.
Finally I re-install the 1.0 version (grab from trash)… but not satisfied with that.

Hi.
If the library is choosing the Ticker v1.0 is because that’s the one compatible.
You should use that and not the other one.
Regards,
Sara

That’s what i did. I’m not able to modified the code to emplement “new” Ticker yet.
Thanks.

I’ll mark this issue as resolved. If you need further help, you just need to open a new question in our forum.
Regards,
Sara