diff --git a/conf/app.src b/conf/app.src
index ae7e903..188f1b5 100644
--- a/conf/app.src
+++ b/conf/app.src
@@ -3,4 +3,3 @@ SOURCE_SUM=6bdb9f9e629d942c81b4228ba3b49749ddf5e2b7e3c484540adb4196c43efc44
 SOURCE_SUM_PRG=sha256sum
 SOURCE_FORMAT=tar.gz
 SOURCE_IN_SUBDIR=true
-SOURCE_FILENAME=
diff --git a/manifest.json b/manifest.json
index 8b8fc4c..fef47ba 100644
--- a/manifest.json
+++ b/manifest.json
@@ -13,7 +13,7 @@
         "name": "eric_G"
     },
     "requirements": {
-        "yunohost": ">= 4.1.7"
+        "yunohost": ">= 4.2.3"
     },
     "multi_instance": false,
     "services": [
@@ -23,8 +23,7 @@
         "install" : [
             {
                 "name": "domain",
-                "type": "domain",
-                "example": "domain.org"
+                "type": "domain"
             },
             {
                 "name": "path",
diff --git a/scripts/backup b/scripts/backup
index 43b5bd2..1724afa 100644
--- a/scripts/backup
+++ b/scripts/backup
@@ -28,6 +28,7 @@ app=$YNH_APP_INSTANCE_NAME
 
 final_path=$(ynh_app_setting_get --app=$app --key=final_path)
 domain=$(ynh_app_setting_get --app=$app --key=domain)
+data_path=$(ynh_app_setting_get --app=$app --key=data_path)
 
 #=================================================
 # DECLARE DATA AND CONF FILES TO BACKUP
@@ -47,12 +48,18 @@ ynh_backup --src_path="$final_path"
 ynh_backup --src_path="/etc/nginx/conf.d/$domain.d/$app.conf"
 
 #=================================================
-# SPECIFIC BACKUP
-#=================================================
-# BACKUP DATADIR DIRECTORY
+# BACKUP THE DATA DIR
 #=================================================
 
-ynh_backup --src_path="/home/yunohost.app/$app"
+ynh_backup --src_path="$data_path" --is_big
+
+#=================================================
+# SPECIFIC BACKUP
+#=================================================
+# BACKUP LOGROTATE
+#=================================================
+
+ynh_backup --src_path="/etc/logrotate.d/$app"
 
 #=================================================
 # BACKUP SYSTEMD
diff --git a/scripts/install b/scripts/install
index 99536a1..39c746e 100644
--- a/scripts/install
+++ b/scripts/install
@@ -67,6 +67,14 @@ ynh_script_progression --message="Installing dependencies..." --weight=2
 # Install Nodejs
 ynh_exec_warn_less ynh_install_nodejs --nodejs_version=$nodejs_version
 
+#=================================================
+# CREATE DEDICATED USER
+#=================================================
+ynh_script_progression --message="Configuring system user..." --weight=1
+
+# Create a system user
+ynh_system_user_create --username=$app --home_dir=$final_path
+
 #=================================================
 # DOWNLOAD, CHECK AND UNPACK SOURCE
 #=================================================
@@ -76,6 +84,10 @@ ynh_app_setting_set --app=$app --key=final_path --value=$final_path
 # Download, check integrity, uncompress and patch the source from app.src
 ynh_setup_source --dest_dir=$final_path
 
+chmod 750 "$final_path"
+chmod -R o-rwx "$final_path"
+chown -R $app:www-data "$final_path"
+
 #=================================================
 # NGINX CONFIGURATION
 #=================================================
@@ -84,14 +96,6 @@ ynh_script_progression --message="Configuring NGINX web server..." --weight=3
 # Create a dedicated NGINX config
 ynh_add_nginx_config
 
-#=================================================
-# CREATE DEDICATED USER
-#=================================================
-ynh_script_progression --message="Configuring system user..." --weight=1
-
-# Create a system user
-ynh_system_user_create --username=$app --home_dir=$final_path
-
 #=================================================
 # SPECIFIC SETUP
 #==============================================
@@ -99,10 +103,10 @@ ynh_system_user_create --username=$app --home_dir=$final_path
 #==============================================
 ynh_script_progression --message="Building $app... (this will take some time and resources!)" --weight=26
 
-pushd "$final_path" || ynh_die
+pushd "$final_path"
 	ynh_use_nodejs
 	ynh_exec_warn_less ynh_npm install
-popd || ynh_die
+popd
 
 #=================================================
 # CREATE DIRECTORY FOR DATA AND CONFIG
@@ -110,16 +114,18 @@ popd || ynh_die
 ynh_script_progression --message="Creating the data directory..." --weight=1
 
 # Define app's data directory
-data_path="/home/yunohost.app/${app}"
+data_path=/home/yunohost.app/$app
+ynh_app_setting_set --app=$app --key=data_path --value=$data_path
 
 # Create datadir folder
 mkdir -p $data_path
-
 # Create config folder
 mkdir -p $final_path/config
 
 # Give permission to the datadir
-chown -R $app: "$data_path"
+chmod 750 "$data_path"
+chmod -R o-rwx "$data_path"
+chown -R $app:www-data "$data_path"
 
 #=================================================
 # SETUP SYSTEMD
@@ -127,7 +133,6 @@ chown -R $app: "$data_path"
 ynh_script_progression --message="Configuring a systemd service..." --weight=1
 
 ynh_replace_string --match_string="__ENV_PATH__" --replace_string="$PATH"    --target_file="../conf/systemd.service"
-ynh_replace_string --match_string="__YNH_NPM__"  --replace_string="$ynh_npm" --target_file="../conf/systemd.service"
 
 ynh_add_systemd_config
 
@@ -137,18 +142,18 @@ ynh_add_systemd_config
 ynh_script_progression --message="Modifying a config file..." --weight=1
 
 ynh_add_config --template="../conf/config.json.example" --destination="$final_path/config/config.json"
+chmod 600 "$final_path/config/config.json"
+chown $app:$app "$final_path/config/config.json"
 
 #=================================================
 # GENERIC FINALIZATION
 #=================================================
-# SECURE FILES AND DIRECTORIES
+# SETUP LOGROTATE
 #=================================================
-ynh_script_progression --message="Securing files and directories..." --weight=1
+ynh_script_progression --message="Configuring log rotation..." --weight=1
 
-# Set permissions to app files
-chown -R $app: $final_path
-chmod 755 $final_path
-chmod 600 $final_path/config/config.json
+# Use logrotate to manage application logfile(s)
+ynh_use_logrotate
 
 #=================================================
 # INTEGRATE SERVICE IN YUNOHOST
diff --git a/scripts/remove b/scripts/remove
index 92f6166..a307093 100644
--- a/scripts/remove
+++ b/scripts/remove
@@ -19,6 +19,7 @@ app=$YNH_APP_INSTANCE_NAME
 domain=$(ynh_app_setting_get --app=$app --key=domain)
 port=$(ynh_app_setting_get --app=$app --key=port)
 final_path=$(ynh_app_setting_get --app=$app --key=final_path)
+data_path=$(ynh_app_setting_get --app=$app --key=data_path)
 
 #=================================================
 # STANDARD REMOVE
@@ -56,11 +57,15 @@ ynh_script_progression --message="Removing app main directory..." --weight=6
 ynh_secure_remove --file="$final_path"
 
 #=================================================
-# REMOVE DATADIR DIRECTORY
+# REMOVE DATA DIR
 #=================================================
 
-ynh_secure_remove --file="/home/yunohost.app/$app"
-
+# Remove the data directory if --purge option is used
+if [ "${YNH_APP_PURGE:-0}" -eq 1 ]
+then
+	ynh_script_progression --message="Removing app data directory..." --weight=1
+	ynh_secure_remove --file="$datadir"
+fi
 #=================================================
 # REMOVE NGINX CONFIGURATION
 #=================================================
diff --git a/scripts/restore b/scripts/restore
index 5276b01..ef90181 100644
--- a/scripts/restore
+++ b/scripts/restore
@@ -35,8 +35,6 @@ final_path=$(ynh_app_setting_get --app=$app --key=final_path)
 #=================================================
 ynh_script_progression --message="Validating restoration parameters..." --weight=2
 
-ynh_webpath_available --domain=$domain --path_url=$path_url \
-	|| ynh_die --message="Path not available: ${domain}${path_url}"
 test ! -d $final_path \
 	|| ynh_die --message="There is already a directory: $final_path "
 
@@ -64,14 +62,9 @@ ynh_script_progression --message="Restoring $app main directory..." --weight=20
 
 ynh_restore_file --origin_path="$final_path"
 
-#=================================================
-# RESTORE USER RIGHTS
-#=================================================
-ynh_script_progression --message="Restoring user rights..."
-
-# Restore permissions on app files
-chown -R $app:$app $final_path
-chmod 755 $final_path
+chmod 750 "$final_path"
+chmod -R o-rwx "$final_path"
+chown -R $app:www-data "$final_path"
 
 #=================================================
 # SPECIFIC RESTORATION
@@ -92,12 +85,24 @@ ynh_restore_file --origin_path="/etc/systemd/system/$app.service"
 systemctl enable $app.service --quiet
 
 #=================================================
-# RESTORE VARIOUS FILES
+# RESTORE THE DATA DIRECTORY
 #=================================================
+ynh_script_progression --message="Restoring the data directory..." --weight=1
 
-ynh_restore_file "/home/yunohost.app/$app"
-chown -R $app: "/home/yunohost.app/$app"
-chmod 600 $final_path/config/config.json
+ynh_restore_file --origin_path="$data_path" --not_mandatory
+
+mkdir -p $data_path
+
+chmod 750 "$data_path"
+chmod -R o-rwx "$data_path"
+chown -R $app:www-data "$data_path"
+
+#=================================================
+# RESTORE THE LOGROTATE CONFIGURATION
+#=================================================
+ynh_script_progression --message="Restoring the logrotate configuration..." --weight=1
+
+ynh_restore_file --origin_path="/etc/logrotate.d/$app"
 
 #=================================================
 # INTEGRATE SERVICE IN YUNOHOST
@@ -109,7 +114,7 @@ yunohost service add $app --description="Self-hosted file storage server" --log=
 #=================================================
 # START SYSTEMD SERVICE
 #=================================================
-ynh_script_progression --message="Starting a systemd service..." --weight=40
+ynh_script_progression --message="Starting a systemd service..." --weight=20
 
 ynh_systemd_action --service_name=$app --action=start --log_path=systemd --line_match="Ready for requests!"
 
diff --git a/scripts/upgrade b/scripts/upgrade
index 66866c6..4e1f5b0 100644
--- a/scripts/upgrade
+++ b/scripts/upgrade
@@ -24,22 +24,9 @@ port=$(ynh_app_setting_get --app=$app --key=port)
 #=================================================
 # CHECK VERSION
 #=================================================
-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
 #=================================================
@@ -54,6 +41,18 @@ ynh_clean_setup () {
 # Exit if an error occurs during the execution of the script
 ynh_abort_if_errors
 
+#=================================================
+# 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=$app --key=is_public
+fi
+
 #=================================================
 # STANDARD UPGRADE STEPS
 #=================================================
@@ -86,6 +85,10 @@ then
 	ynh_setup_source --dest_dir=$final_path
 fi
 
+chmod 750 "$final_path"
+chmod -R o-rwx "$final_path"
+chown -R $app:www-data "$final_path"
+
 #=================================================
 # NGINX CONFIGURATION
 #=================================================
@@ -107,39 +110,25 @@ ynh_exec_warn_less ynh_install_nodejs --nodejs_version=$nodejs_version
 #==============================================
 # INSTALL DROPPY
 #==============================================
+
 if [ "$upgrade_type" == "UPGRADE_APP" ]
 then
 	ynh_script_progression --message="Building $app... (this will take some time and resources!)" --weight=25
 
-	pushd "$final_path" || ynh_die
+	pushd "$final_path"
 		ynh_use_nodejs
 		ynh_exec_warn_less ynh_npm install
-	popd || ynh_die
+	popd
 fi
 
-#=================================================
-# CREATE DIRECTORY FOR DATA AND CONFIG
-#=================================================
-ynh_script_progression --message="Creating the data directory..." --weight=1
-
-# Define app's data directory
-data_path="/home/yunohost.app/${app}"
-
-# Create datadir folder
-mkdir -p $data_path
-
-# Create config folder
-mkdir -p $final_path/config
-
-# Give permission to the datadir
-chown -R $app:$app "$data_path"
-
 #=================================================
 # MODIFY A CONFIG FILE
 #=================================================
 ynh_script_progression --message="Modifying a config file..." --weight=2
 
 ynh_add_config --template="../conf/config.json.example" --destination="$final_path/config/config.json"
+chmod 600 "$final_path/config/config.json"
+chown $app:$app "$final_path/config/config.json"
 
 #=================================================
 # SETUP SYSTEMD
@@ -147,7 +136,6 @@ ynh_add_config --template="../conf/config.json.example" --destination="$final_pa
 ynh_script_progression --message="Configuring a systemd service..." --weight=2
 
 ynh_replace_string --match_string="__ENV_PATH__" --replace_string="$PATH"    --target_file="../conf/systemd.service"
-ynh_replace_string --match_string="__YNH_NPM__"  --replace_string="$ynh_npm" --target_file="../conf/systemd.service"
 
 # Create a dedicated systemd config
 ynh_add_systemd_config
@@ -155,14 +143,12 @@ ynh_add_systemd_config
 #=================================================
 # GENERIC FINALIZATION
 #=================================================
-# SECURE FILES AND DIRECTORIES
+# SETUP LOGROTATE
 #=================================================
-ynh_script_progression --message="Securing files and directories..." --weight=2
+ynh_script_progression --message="Upgrading logrotate configuration..." --weight=1
 
-# Set permissions on app files
-chown -R $app:$app $final_path
-chmod 755 $final_path
-chmod 600 $final_path/config/config.json
+# Use logrotate to manage app-specific logfile(s)
+ynh_use_logrotate --non-append
 
 #=================================================
 # INTEGRATE SERVICE IN YUNOHOST
@@ -174,7 +160,7 @@ yunohost service add $app --description="Self-hosted file storage server" --log=
 #=================================================
 # START SYSTEMD SERVICE
 #=================================================
-ynh_script_progression --message="Starting a systemd service..." --weight=40
+ynh_script_progression --message="Starting a systemd service..." --weight=20
 
 ynh_systemd_action --service_name=$app --action=start --log_path=systemd --line_match="Ready for requests!"