Understanding SAP Front End Server (FES) versions/UI5 Versions/
SAP Fiori apps require front-end components (providing the user interface and the connection to the back end) and back-end components (providing the data).
Newer SAP Fiori app front-end components require “SAP Fiori Front-End Server” (FES) based on NetWeaver AS ABAP for deployment. The following list shows the available product versions of front-end servers ordered by release date and the comprised components:
SAPUI5 Maintenance Versions Overview
SAP_UI On-premise Maintenance Versions With Minimum AS ABAP Shipment Stack