CCSE
https://training-certifications.checkpoint.com/#/courses/Check%20Point%20Certified%20Expert%20(CCSE)%20R80.x
This section provides instructions to upgrade Multi-Domain Servers and Multi-Domain Log Servers:
Upgrading one Multi-Domain Server from R80.20 and higher
Upgrading Multi-Domain Servers in High Availability from R80.20 and higher
Upgrading a Multi-Domain Log Server from R80.20 and higher