Current Kernel release can be grouped into three kernel code lines : 72x kernel, the 74x/75x kernel , and the 77x/78x Kernel.
Kernel 721 is the latest kernel supporting 32-bit platform (Out of Maintenance since January 1st 2021 #sap #maintenance # )
72x kernel : supports SAP BS 6.0 (EHP <=6) with SAP NW 7.0 to 7.3 EHP1, contains kernel 720,721,722 and variants ext adn ex2 (these kernel version supports more recent OS and DB Platform as well as new compiler) SAP NOTE : 1744209
74x and 75x Kernel : supports SAP BS 6.0 (EHP 7 and EHP 8) as well as SAP S/4 HANA release 1511,1610,1709. corresponds to SAP NW 7.4 and 7.5 and SAP NW AS 7.51 and 7.52 SAP NOTE : 1969546
77x and 78X Kernel : supports recent SAP S/4 HANA 1809 on, it contains kernel 773 and following. SAP NOTE : 2907361