From 0202e01b9e3d9574a38db3dd44670abf74611fc2 Mon Sep 17 00:00:00 2001
From: eteixido1 <52964958+eteixido1@users.noreply.github.com>
Date: Wed, 7 Aug 2019 13:33:17 +0200
Subject: [PATCH] docker.md

In my case I'm unable to compiling with ubuntu 18 and 19 with a critical error with M4 and GCC 2.28. I think that information will help other users.
---
 doc/docker.md | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/doc/docker.md b/doc/docker.md
index 99cb2d0f..86847bf7 100644
--- a/doc/docker.md
+++ b/doc/docker.md
@@ -4,6 +4,12 @@ Docker is well known among software developers. Even if you are not familiar wit
 
 ## Build openfang using pre-built docker image (recommended)
 
+! Some users have problems compiling Openfang with GCC 2.28 and M4 (Ubuntu 18 or later ). We recomend Ubuntu 16.04.6 LTS to deploy Openfang docker. Make sure that you have the following packages in the system:
+
+```
+sudo apt install gcc g++ python make m4 zip unzip lzop
+```
+
 The next set of commands will retrieve the image from dockerhub and compile it. To do so, use the following commands:
 
 ```