diff --git a/doc/02-Installation.md b/doc/02-Installation.md
index 789c2e128..c99b84205 100644
--- a/doc/02-Installation.md
+++ b/doc/02-Installation.md
@@ -11,6 +11,7 @@ thoroughly.
 
 * A web server, e.g. Apache or nginx
 * PHP >= 5.3.0 w/ gettext, intl and OpenSSL support
+* Default time zone configured for PHP in the php.ini file
 * LDAP PHP library when using Active Directory or LDAP for authentication
 * Icinga 1.x w/ IDO; Icinga 2.x w/ IDO feature enabled
 * The IDO table prefix must be icinga_ which is the default