diff --git a/scripts/backup b/scripts/backup
index b914d0a..da46623 100644
--- a/scripts/backup
+++ b/scripts/backup
@@ -32,6 +32,7 @@ app=$YNH_APP_INSTANCE_NAME
 final_path=$(ynh_app_setting_get --app=$app --key=final_path)
 domain=$(ynh_app_setting_get --app=$app --key=domain)
 db_name=$(ynh_app_setting_get --app=$app --key=db_name)
+unicorn_workers=$(ynh_app_setting_get --app=$app --key=unicorn_workers)
 
 #=================================================
 # STANDARD BACKUP STEPS
diff --git a/scripts/change_url b/scripts/change_url
index c92e307..b062d9b 100644
--- a/scripts/change_url
+++ b/scripts/change_url
@@ -34,6 +34,7 @@ final_path=$(ynh_app_setting_get --app=$app --key=final_path)
 db_name=$(ynh_app_setting_get --app=$app --key=db_name)
 db_user=$db_name
 db_pwd=$(ynh_app_setting_get --app=$app --key=db_pwd)
+unicorn_workers=$(ynh_app_setting_get --app=$app --key=unicorn_workers)
 
 #=================================================
 # BACKUP BEFORE UPGRADE THEN ACTIVE TRAP
@@ -151,11 +152,6 @@ $rake_exec posts:rebake
 ynh_print_info --message="Starting a systemd service..."
 
 # Start a systemd service
-if [ -n "$(uname -m | grep arm)" ] ; then
-	unicorn_workers=2
-else
-	unicorn_workers=3
-fi
 ynh_systemd_action --service_name=$app --action="start" --log_path="$final_path/log/unicorn.stderr.log" --line_match="INFO -- : worker=$((unicorn_workers-1)) ready"
 
 #=================================================
diff --git a/scripts/install b/scripts/install
index 453e0c2..a65fa11 100644
--- a/scripts/install
+++ b/scripts/install
@@ -312,6 +312,8 @@ else
 	additional_env=""
 	unicorn_workers=3
 fi
+ynh_app_setting_set --app=$app --key=unicorn_workers --value=$unicorn_workers
+
 ynh_replace_string --match_string="__ADDITIONAL_ENV__" --replace_string="$additional_env" --target_file="../conf/systemd.service"
 ynh_replace_string --match_string="__LIBJEMALLOC__" --replace_string="$(ldconfig -p | grep libjemalloc | awk 'END {print $NF}')" --target_file="../conf/systemd.service"
 ynh_add_systemd_config
diff --git a/scripts/restore b/scripts/restore
index 35d674e..1b8f079 100644
--- a/scripts/restore
+++ b/scripts/restore
@@ -144,6 +144,7 @@ if [ -n "$(uname -m | grep arm)" ] ; then
 else
 	unicorn_workers=3
 fi
+ynh_app_setting_set --app=$app --key=unicorn_workers --value=$unicorn_workers
 ynh_systemd_action --service_name=$app --action="start" --log_path="$final_path/log/unicorn.stderr.log" --line_match="INFO -- : worker=$((unicorn_workers-1)) ready"
 
 #=================================================
diff --git a/scripts/upgrade b/scripts/upgrade
index abd31f5..29543da 100644
--- a/scripts/upgrade
+++ b/scripts/upgrade
@@ -24,6 +24,7 @@ final_path=$(ynh_app_setting_get --app=$app --key=final_path)
 db_name=$(ynh_app_setting_get --app=$app --key=db_name)
 db_pwd=$(ynh_app_setting_get --app=$app --key=db_pwd)
 redis_db=$(ynh_app_setting_get --app=$app --key=redis_db)
+unicorn_workers=$(ynh_app_setting_get --app=$app --key=unicorn_workers)
 
 # Check memory requirements
 check_memory_requirements_upgrade
@@ -35,6 +36,25 @@ ynh_print_info --message="Checking version..."
 
 upgrade_type=$(ynh_check_app_version_changed)
 
+#=================================================
+# ENSURE DOWNWARD COMPATIBILITY
+#=================================================
+ynh_script_progression --message="Ensuring downward compatibility..." --weight=1
+
+# If db_name doesn't exist, create it
+if [ -z "$unicorn_workers" ]
+then
+	# We assume for the moment that ARM devices are only dual core, so
+	# we restrict the number of workers to 2 (the default is 3)
+	if [ -n "$(uname -m | grep arm)" ]
+	then
+		unicorn_workers=2
+	else
+		unicorn_workers=3
+	fi
+	ynh_app_setting_set --app=$app --key=unicorn_workers --value=$unicorn_workers
+fi
+
 #=================================================
 # BACKUP BEFORE UPGRADE THEN ACTIVE TRAP
 #=================================================
@@ -286,16 +306,7 @@ ynh_print_info --message="Configuring a systemd service..."
 
 ynh_replace_string --match_string="__RBENVROOT__" --replace_string="$RBENV_ROOT" --target_file="../conf/systemd.service"
 
-# We assume for the moment that ARM devices are only dual core, so
-# we restrict the number of workers to 2 (the default is 3)
-if [ -n "$(uname -m | grep arm)" ] ; then
-	additional_env="UNICORN_WORKERS=2"
-	unicorn_workers=2
-else
-	additional_env=""
-	unicorn_workers=3
-fi
-
+additional_env="UNICORN_WORKERS=$unicorn_workers"
 ynh_replace_string --match_string="__ADDITIONAL_ENV__" --replace_string="$additional_env" --target_file="../conf/systemd.service"
 ynh_replace_string --match_string="__LIBJEMALLOC__" --replace_string="$(ldconfig -p | grep libjemalloc | awk 'END {print $NF}')" --target_file="../conf/systemd.service"
 ynh_add_systemd_config
@@ -341,11 +352,6 @@ fi
 #=================================================
 ynh_print_info --message="Starting a systemd service..."
 
-if [ -n "$(uname -m | grep arm)" ] ; then
-	unicorn_workers=2
-else
-	unicorn_workers=3
-fi
 # Wait for discourse to be fully started
 ynh_systemd_action --service_name=$app --action="start" --log_path="$final_path/log/unicorn.stderr.log" --line_match="INFO -- : worker=$((unicorn_workers-1)) ready"