SAP kernel patching

SAP kernel is the central software for the ABAP netweaver stack. It also contains bug and needs patching/updating from time to time.

Unlike support packages and OSS notes, the kernel patching has to be handled with more care.

Questions that will be answered in this blog are:

  • What is the SAP kernel deployment strategy?
  • When should I patch the SAP kernel?
  • What are known pain point in SAP kernel updates?
  • Where can I find kernel OSS notes updates?
  • Where can I find regressions on kernel updates?

SAP kernel deployment strategy

The full SAP kernel deployment strategy can be found as document on this link.

The basic strategy:

  • Update kernel with support package upgrade or main version upgrade
  • Apply kernel updates only when you experience issues

This is a sound approach. The kernel is quite black and white in updating. It is fully updated or not. Each new kernel might contain new bugs or unwanted side effects. If not properly tested you need to roll back the kernel update.

SAP kernel versions and SAP kernel patch levels

Versions and levels can be found in OSS note 2083594 – SAP Kernel Versions and SAP Kernel Patch Levels.

Known pain points in kernel updates

If you upgrade your SAP kernel, please pay attention to the following items:

  • Use of ITS webgui
    • Use of handheld scanners using the ITS webgui
    • Portal and other external integration of ITS webgui
    • Browser applications using ITS webgui
  • Logon issues:
    • RFC
    • SNC
    • SSO
    • SAML2
    • LDAP connector
    • http(s)
  • SAP screen personas and other screen scraping tools like robotics process automation tools
  • ACF framework (do not use if possible, see blog)

Best practice is to assemble these test scenarios in your company. This way you know next time which tests to perform when applying a kernel patch or kernel update. The tests you execute on an acceptance or quality system before applying the kernel update to your productive system.

Kernel regression OSS note

SAP OSS note 1802333 – Finding information about regressions in the SAP kernel describes how to find the needed regression note for your SAP kernel. The regression notes describe the unwanted side effects and bugs in the kernels.

Kernel roadmap OSS notes

Roadmap OSS notes:

Business suite EHP8 and S4HANA till 1710: 1969546 – Release Roadmap for Kernel 74x and 75x.

S4HANA 1809, 1909 and 2020: 2907361 – Release Roadmap for Kernel 77x and 78x.

Kernel update information

News update on kernel are published on SAP wiki for kernel.