'class ESP8266WebServer' has no member named 'setNoDelay'

Following the latest ESP8266 Arduino Core documentation (2.4.1) at
http://arduino-esp8266.readthedocs.io/en/latest/esp8266wifi/server-class.html
there should exist a function setNoDelay() to enable/disable Nagle,

server.setNoDelay(true);

Trying to use this function, I get the following error:

exit status 1
'class ESP8266WebServer' has no member named 'setNoDelay'

same problem for function
server.status();

I checked esp8266 module in boardmanager = 2.4.1

What's the problem?

possibly you installed wrong library

I've added screenshot of installed esp8266 version.
Do I need a different version to use these functions?

... no ideas ?

snaudi:
... no ideas ?

No code to look at!