diff --git a/README.md b/README.md
index 7c1b4ac..3740e0b 100644
--- a/README.md
+++ b/README.md
@@ -26,7 +26,6 @@ Shared files are stored in the following directory: `/home/yunohost.app/droppy/f
 ## Documentation
 
  * Official documentation: https://github.com/silverwind/droppy
- * YunoHost documentation: 
 
 ## YunoHost specific features
 
diff --git a/README_fr.md b/README_fr.md
index c458d16..e9c58fc 100644
--- a/README_fr.md
+++ b/README_fr.md
@@ -26,7 +26,6 @@ Les fichiers partagés sont stockés dans le répertoire suivant : `/home/yunoho
 ## Documentation
 
  * Documentation officielle : https://github.com/silverwind/droppy
- * Documentation YunoHost : 
 
 ## Caractéristiques spécifiques YunoHost
 
diff --git a/manifest.json b/manifest.json
index 582bd57..9476910 100644
--- a/manifest.json
+++ b/manifest.json
@@ -13,7 +13,7 @@
         "name": "eric_G"
     },
     "requirements": {
-        "yunohost": ">= 3.8.1"
+        "yunohost": ">= 4.1.7"
     },
     "multi_instance": false,
     "services": [
diff --git a/scripts/install b/scripts/install
index 48e8cb7..0ed62e5 100644
--- a/scripts/install
+++ b/scripts/install
@@ -47,7 +47,6 @@ ynh_script_progression --message="Storing installation settings..." --weight=2
 
 ynh_app_setting_set --app=$app --key=domain    --value=$domain
 ynh_app_setting_set --app=$app --key=path      --value=$path_url
-ynh_app_setting_set --app=$app --key=is_public --value=$is_public
 
 #=================================================
 # STANDARD MODIFICATIONS
diff --git a/scripts/upgrade b/scripts/upgrade
index 119d625..e426619 100644
--- a/scripts/upgrade
+++ b/scripts/upgrade
@@ -18,7 +18,6 @@ app=$YNH_APP_INSTANCE_NAME
 
 domain=$(ynh_app_setting_get --app=$app --key=domain)
 path_url=$(ynh_app_setting_get --app=$app --key=path)
-is_public=$(ynh_app_setting_get --app=$app --key=is_public)
 final_path=$(ynh_app_setting_get --app=$app --key=final_path)
 port=$(ynh_app_setting_get --app=$app --key=port)
 
@@ -29,10 +28,22 @@ ynh_script_progression --message="Checking version..." --weight=1
 
 upgrade_type=$(ynh_check_app_version_changed)
 
+#=================================================
+# ENSURE DOWNWARD COMPATIBILITY
+#=================================================
+ynh_script_progression --message="Ensuring downward compatibility..." --weight=1
+
+# Cleaning legacy permissions
+if ynh_legacy_permissions_exists; then
+	ynh_legacy_permissions_delete_all
+
+	ynh_app_setting_delete --app=$app --key=is_public
+fi
+
 #=================================================
 # BACKUP BEFORE UPGRADE THEN ACTIVE TRAP
 #=================================================
-ynh_script_progression --message="Backing up $app before upgrading (may take a while)..." --weight=40
+ynh_script_progression --message="Backing up $app before upgrading (may take a while)..." --weight=2
 
 # Backup the current version of the app
 ynh_backup_before_upgrade
@@ -48,9 +59,9 @@ ynh_abort_if_errors
 #=================================================
 # STOP SYSTEMD SERVICE
 #=================================================
-ynh_script_progression --message="Stopping a systemd service..." --weight=1
+ynh_script_progression --message="Stopping a systemd service..." --weight=9
 
-ynh_systemd_action --service_name=$app --action="stop" --log_path="systemd"
+ynh_systemd_action --service_name=$app --action=stop --log_path=systemd
 
 #=================================================
 # DOWNLOAD, CHECK AND UNPACK SOURCE
@@ -172,7 +183,7 @@ yunohost service add $app --description="Self-hosted file storage server" --log=
 #=================================================
 ynh_script_progression --message="Starting a systemd service..." --weight=40
 
-ynh_systemd_action --service_name=$app --action="start" --log_path="systemd" --line_match="Ready for requests!"
+ynh_systemd_action --service_name=$app --action=start --log_path=systemd --line_match="Ready for requests!"
 
 #=================================================
 # RELOAD NGINX