diff --git a/doc/ADMIN.md b/doc/ADMIN.md
new file mode 100644
index 0000000..5b718a3
--- /dev/null
+++ b/doc/ADMIN.md
@@ -0,0 +1,5 @@
+Important Security Note
+
+We do not recommend running Element from the same domain name as your Matrix homeserver (Synapse). The reason is the risk of XSS (cross-site-scripting) vulnerabilities that could occur if someone caused Element to load and render malicious user generated content from a Matrix API which then had trusted access to Element (or other apps) due to sharing the same domain.
+
+We have put some coarse mitigations into place to try to protect against this situation, but it's still not good practice to do it in the first place. See vector-im/element-web#1977 for more details.
\ No newline at end of file
diff --git a/doc/ADMIN_fr.md b/doc/ADMIN_fr.md
new file mode 100644
index 0000000..e69de29
diff --git a/scripts/upgrade b/scripts/upgrade
index 03722f0..8ae8200 100644
--- a/scripts/upgrade
+++ b/scripts/upgrade
@@ -40,7 +40,7 @@ then
 	ynh_script_progression --message="Upgrading source files..." --weight=1
 
 	# Download, check integrity, uncompress and patch the source from app.src
-	ynh_setup_source --dest_dir="$install_dir" #--keep="config.json"
+	ynh_setup_source --dest_dir="$install_dir" --keep="config.json"
 fi
 
 # Set permissions to app files
@@ -50,12 +50,12 @@ chown -R $app:www-data "$install_dir"
 #=================================================
 # ADD A CONFIGURATION
 #=================================================
-ynh_script_progression --message="Adding a configuration file..." --weight=1
+#ynh_script_progression --message="Adding a configuration file..." --weight=1
 
-ynh_add_config --template="../conf/config.json" --destination="$install_dir/config.json"
+#ynh_add_config --template="../conf/config.json" --destination="$install_dir/config.json"
 
-chmod 400 "$install_dir/config.json"
-chown $app:$app "$install_dir/config.json"
+#chmod 400 "$install_dir/config.json"
+#chown $app:$app "$install_dir/config.json"
 
 #=================================================
 # NGINX CONFIGURATION