diff --git a/config_panel.toml b/config_panel.toml
new file mode 100644
index 0000000..b6df29f
--- /dev/null
+++ b/config_panel.toml
@@ -0,0 +1,25 @@
+version = "1.0"
+
+[main]
+name = "Bookstack configuration"
+
+    [main.php_fpm_config]
+    name = "PHP-FPM configuration"
+
+        [main.php_fpm_config.fpm_footprint]
+        ask = "Memory footprint of the service?"
+        choices = ["low", "medium", "high", "specific"]
+        default = "low"
+        help = "low <= 20Mb per pool. medium between 20Mb and 40Mb per pool. high > 40Mb per pool.<br>Use specific to set a value with the following option."
+
+        [main.php_fpm_config.free_footprint]
+        ask = "Memory footprint of the service?"
+        type = "number"
+        default = "0"
+        help = "Free field to specify exactly the footprint in Mb if you don't want to use one of the three previous values."
+
+        [main.php_fpm_config.fpm_usage]
+        ask = "Expected usage of the service?"
+        choices = ["low", "medium", "high"]
+        default = "low"
+        help = "low: Personal usage, behind the SSO. No RAM footprint when not used, but the impact on the processor can be high if many users are using the service.<br>medium: Low usage, few people or/and publicly accessible. Low RAM footprint, medium processor footprint when used.<br>high: High usage, frequently visited website. High RAM footprint, but lower on processor usage and quickly responding."
diff --git a/scripts/config b/scripts/config
new file mode 100644
index 0000000..3440bd2
--- /dev/null
+++ b/scripts/config
@@ -0,0 +1,95 @@
+#!/bin/bash
+
+#=================================================
+# GENERIC STARTING
+#=================================================
+# IMPORT GENERIC HELPERS
+#=================================================
+
+source _common.sh
+source /usr/share/yunohost/helpers
+
+ynh_abort_if_errors
+
+#=================================================
+# RETRIEVE ARGUMENTS
+#=================================================
+
+phpversion=$(ynh_app_setting_get --app=$app --key=phpversion)
+current_fpm_footprint=$(ynh_app_setting_get --app=$app --key=fpm_footprint)
+
+#=================================================
+# SPECIFIC GETTERS FOR TOML SHORT KEY
+#=================================================
+
+get__fpm_footprint() {
+    # Free footprint value for php-fpm
+    # Check if current_fpm_footprint is an integer
+    if [ "$current_fpm_footprint" -eq "$current_fpm_footprint" ] 2> /dev/null
+    then
+        echo "specific"
+    else
+        echo "$current_fpm_footprint"
+    fi
+}
+
+get__free_footprint() {
+    # Free footprint value for php-fpm
+    # Check if current_fpm_footprint is an integer
+    if [ "$current_fpm_footprint" -eq "$current_fpm_footprint" ] 2> /dev/null
+    then
+        # If current_fpm_footprint is an integer, that's a numeric value for the footprint
+        echo "$current_fpm_footprint"
+    else
+        echo "0"
+    fi
+}
+
+#=================================================
+# SPECIFIC SETTERS FOR TOML SHORT KEYS
+#=================================================
+
+set__fpm_footprint() {
+    if [ "$fpm_footprint" != "specific" ]
+    then
+        ynh_app_setting_set --app=$app --key=fpm_footprint --value="$fpm_footprint"
+    fi
+}
+
+set__free_footprint() {
+    if [ "$fpm_footprint" = "specific" ]
+    then
+        ynh_app_setting_set --app=$app --key=fpm_footprint --value="$free_footprint"
+    fi
+}
+
+#=================================================
+# GENERIC FINALIZATION
+#=================================================
+
+ynh_app_config_validate() {
+    _ynh_app_config_validate
+
+    if [ "${changed[fpm_usage]}" == "true" ] || [ "${changed[fpm_footprint]}" == "true" ] || [ "${changed[free_footprint]}" == "true" ]; then
+        # If fpm_footprint is set to 'specific', use $free_footprint value.
+        if [ "$fpm_footprint" = "specific" ]
+        then
+            fpm_footprint=$free_footprint
+        fi
+
+        if [ "$fpm_footprint" == "0" ]
+        then
+            ynh_print_err --message="When selecting 'specific', you have to set a footprint value into the field below."
+
+            exit 0
+        fi
+    fi
+}
+
+ynh_app_config_apply() {
+    _ynh_app_config_apply
+
+    ynh_add_fpm_config --phpversion=$phpversion --usage=$fpm_usage --footprint=$fpm_footprint
+}
+
+ynh_app_config_run $1
diff --git a/scripts/install b/scripts/install
index a2e885e..558dc90 100644
--- a/scripts/install
+++ b/scripts/install
@@ -105,7 +105,7 @@ ynh_add_nginx_config
 ynh_script_progression --message="Configuring PHP-FPM..." --weight=2
 
 # Create a dedicated PHP-FPM config
-ynh_add_fpm_config
+ynh_add_fpm_config --usage=low --footprint=low
 
 #=================================================
 # INSTALL LYCHEE WITH COMPOSER
diff --git a/scripts/restore b/scripts/restore
index fde38c3..2264171 100644
--- a/scripts/restore
+++ b/scripts/restore
@@ -29,6 +29,9 @@ db_name=$(ynh_app_setting_get --app=$app --key=db_name)
 db_user=$db_name
 phpversion=$YNH_PHP_VERSION
 
+fpm_footprint=$(ynh_app_setting_get --app=$app --key=fpm_footprint)
+fpm_usage=$(ynh_app_setting_get --app=$app --key=fpm_usage)
+
 #=================================================
 # CHECK IF THE APP CAN BE RESTORED
 #=================================================
@@ -80,6 +83,9 @@ ynh_script_progression --message="Reconfiguring PHP-FPM..." --weight=5
 
 ynh_restore_file --origin_path="/etc/php/$phpversion/fpm/pool.d/$app.conf"
 
+# Recreate a dedicated php-fpm config
+ynh_add_fpm_config --usage=$fpm_usage --footprint=$fpm_footprint --phpversion=$phpversion
+
 #=================================================
 # RESTORE THE MYSQL DATABASE
 #=================================================
diff --git a/scripts/upgrade b/scripts/upgrade
index 125665e..926f53a 100644
--- a/scripts/upgrade
+++ b/scripts/upgrade
@@ -27,6 +27,9 @@ phpversion=$YNH_PHP_VERSION
 redis_db=$(ynh_app_setting_get --app=$app --key=redis_db)
 mail_pwd=$(ynh_string_random --length=12)
 
+fpm_footprint=$(ynh_app_setting_get --app=$app --key=fpm_footprint)
+fpm_usage=$(ynh_app_setting_get --app=$app --key=fpm_usage)
+
 #=================================================
 # CHECK VERSION
 #=================================================
@@ -47,6 +50,30 @@ 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
+
+# If fpm_footprint doesn't exist, create it
+if [ -z "$fpm_footprint" ]; then
+	fpm_footprint=low
+	ynh_app_setting_set --app=$app --key=fpm_footprint --value=$fpm_footprint
+fi
+
+# If fpm_usage doesn't exist, create it
+if [ -z "$fpm_usage" ]; then
+	fpm_usage=low
+	ynh_app_setting_set --app=$app --key=fpm_usage --value=$fpm_usage
+fi
+
+# Cleaning legacy permissions
+if ynh_legacy_permissions_exists; then
+	ynh_legacy_permissions_delete_all
+
+	ynh_app_setting_delete --app=$app --key=is_public
+fi
+
 #=================================================
 # CREATE DEDICATED USER
 #=================================================
@@ -88,7 +115,7 @@ ynh_install_app_dependencies $pkg_dependencies
 ynh_script_progression --message="Upgrading PHP-FPM configuration..." --weight=1
 
 # Create a dedicated PHP-FPM config
-ynh_add_fpm_config
+ynh_add_fpm_config --usage=$fpm_usage --footprint=$fpm_footprint
 
 #=================================================
 # INSTALL LYCHEE WITH COMPOSER
@@ -114,7 +141,6 @@ popd
 chmod 755 $final_path
 chmod -R o-rwx $final_path
 chown -R $app:www-data $final_path
-#chmod 600 $final_path/.env
 
 #=================================================
 # RELOAD NGINX