Replace ID with the actual one in Geoserver
General
                  
                      Web Map
                    
                    
                    
                      OGC Standards
                    
                    
                    
                      GeoServer
                    
                    
                  Display the actual id column instead of the auto-generated Feature ID column
Description :
- Make sure that “Expose Primary Keys” option is active in DataStore settings.
 - In WFS services like JSON etc. add formatoptions=idpolicy:reference_no=
at the end of the line.  
See: https://docs.geoserver.org/stable/en/user/services/wfs/outputformats.html
Simple Expression :
Example :
              	 2025 Mar