diff --git a/README.rst b/README.rst
index 5fa04ed..0a5577e 100644
--- a/README.rst
+++ b/README.rst
@@ -9,12 +9,11 @@ An installer which deploy a complete mail server based on Modoboa.
 
    This tool is still in beta stage, it has been tested on:
 
-   * Debian Buster (10) / Bullseye (11)
+   * Debian 10 and upper
    * Ubuntu Bionic Beaver (18.04) and upper
-   * CentOS 7
 
 .. warning::
-      
+
    ``/tmp`` partition must be mounted without the ``noexec`` option.
 
 .. note::
@@ -92,8 +91,8 @@ You can activate it as follows::
 
 It will automatically install latest versions of modoboa and its plugins.
 
-Backup mode 
-------------
+Backup mode
+-----------
 
 An experimental backup mode is available.
 
diff --git a/run.py b/run.py
index d643fc8..6ba87ae 100755
--- a/run.py
+++ b/run.py
@@ -37,6 +37,12 @@ PRIMARY_APPS = [
 def installation_disclaimer(args, config):
     """Display installation disclaimer."""
     hostname = config.get("general", "hostname")
+    utils.printcolor(
+        "Notice:\n"
+        "It is recommanded to run this installer on a FRESHLY installed server.\n"
+        "(ie. with nothing special already installed on it)\n",
+        utils.CYAN
+    )
     utils.printcolor(
         "Warning:\n"
         "Before you start the installation, please make sure the following "
@@ -47,7 +53,7 @@ def installation_disclaimer(args, config):
             hostname.replace(".{}".format(args.domain), ""),
             hostname
         ),
-        utils.CYAN
+        utils.YELLOW
     )
     utils.printcolor(
         "Your mail server will be installed with the following components:",