Add PHP Extension requirements, fixes #394

README.md

@@ -381,11 +381,17 @@ docker-compose -f docker-compose.7.yml up -d
 
 You can then point your browser to http://localhost:8086
 
-## Compatibility
+## PHP Requirements
 
 Daux.io is compatible with PHP 5.5 and up.
 
-The reason is because some dependencies we have (mainly Symfony and Guzzle) do not support php 5.4 anymore
+The reason is because some dependencies we have (mainly Symfony and Guzzle) do not support php 5.4 anymore.
+
+### Extensions
+
+PHP Needs the following extension to work : `php-mbstring` and `php-xml`.
+
+If you encounter an error similar to `utf8_decode() not found` this means that you're missing the `php-xml` package. (We've seen it happen only on PHP 7)
 
 ## Support