You can find the information about which Kernel version is required with which NW release and which NW SP Stack in this post , also the maintenance of each NW Kernel version ends and which higher Kernel version is available as DCK – “Downward Compatible Kernel” in order to apply Kernel patches.

Important information from SAP ;

“NW 7.5 SP0 was released with Kernel version 745. This Kernel version is planned to be stable for each new NW 7.5 SP. In early NW 7.4 SPs the Kernel version changed,”

Usage of this “Downward Compatible Kernel” version in SP stacks down to SP02 is possible.

You can find the updated informations about “SAP Kernel News” in ;

http://scn.sap.com/docs/DOC-53415

Also you can check the following OSS note for updated and detailed “SAP Kernel Informations” in ;

1969546 – Release Roadmap for Kernel 74x and 75x 

How to use “DCK Kernel” in ;

2128122 – Use of 7.42 kernel instead of 7.40 or 7.41 kernel