Your issue is related to SSFS and there is an SAP KBA addressing this issue.
1904826 - Upgrade error "Connect via SAPUSER not supported for kernel >= 740"
You should review the SSFS settings for the primary and shadow instances based on the SAP note 1622837 - Secure connection of AS ABAP to Oracle via SSFS
Read the the section 4: Information about the upgrade from the above note and check whether the parameter rsdb_ssfs_connect = 1 is set correctly.
Cheers
RB