user31852: I am new to Arduino. For the project I am trying to do, I want to install the ESP8266 extension. But the additional boards manager URL option is missing from the Arduino IDE. What should I do to add the extension?

user32391: the URL is the following and the 1.8.2 IDE accepted it: 
http://arduino.esp8266.com/stable/package_esp8266com_index.json
Good luck,
endre
P.s.: I found the answer/URL here:
No Response to AT commands

user26916: You need to download and install a recent version of the Arduino IDE from:
http://www.arduino.cc/en/Main/Software
When you install the Arduino IDE using apt-get you get a very outdated and non-standard version, which does not have the Boards Manager feature. The reason for this is that the license documentation of the Arduino IDE does not currently meet the required standards for the package manager:
https://github.com/arduino/Arduino/pull/2703

31852: <p>I am new to Arduino. For the project I am trying to do, I want to install the ESP8266 extension. But the additional boards manager URL option is missing from the Arduino IDE. What should I do to add the extension?</p>
 32391: <p>the URL is the following and the 1.8.2 IDE accepted it: 
<a href="http://arduino.esp8266.com/stable/package_esp8266com_index.json" rel="nofollow noreferrer">http://arduino.esp8266.com/stable/package_esp8266com_index.json</a></p>

<p>Good luck,
endre</p>

<p>P.s.: I found the answer/URL here:
<a href="https://arduino.stackexchange.com/questions/24391/no-response-to-at-commands/31297#31297">No Response to AT commands</a></p>
 26916: <p>You need to download and install a recent version of the Arduino IDE from:</p>

<p><a href="http://www.arduino.cc/en/Main/Software" rel="noreferrer">http://www.arduino.cc/en/Main/Software</a></p>

<p>When you install the Arduino IDE using <code>apt-get</code> you get a very outdated and non-standard version, which does not have the Boards Manager feature. The reason for this is that the license documentation of the Arduino IDE does not currently meet the required standards for the package manager:</p>

<p><a href="https://github.com/arduino/Arduino/pull/2703" rel="noreferrer">https://github.com/arduino/Arduino/pull/2703</a></p>
