SAP S/4 Hana without Fiori (second question)

Hello,

My company don't use SAP. Now, we are adquiring SAP S/4 Hana, but we will use just classic SAP modules, that is, we will not use the Fiori application. Does the SAP GUI have the same performance as the Fiori apps? Will the SAP GUI be supported after 31 December 2025?

Thank you