From rhn-engineering-bmarzins:

• There is a new "protocol" subsection allowed for the "overrides" section in rhel-9. repos/system_upgrade/common/libraries/multipathutil.py needs to handle it.
• config_dir is deprecated and unused in RHEL-10. The multipath config directory is always "/etc/multipath/conf.d" If this is set in RHEL-9, the config files need to be moved from config_dir to "/etc/multipath/conf.d" in RHEL-10. The config_dir line should also get commented out in RHEL-10, so that multipath doesn't print warning messages.
• bindings_file, wwids_file, and prkeys_file are also deprecated and unused. The default files are always used now (/etc/multipath/bindings, /etc/multipath/wwids, and /etc/multipath/prkeys respectively). If these options are set in the rhel-9 config, those files need to be moved to the default filenames in rhel-10, and the option lines should be commented out in the rhel-10 config.
• multipathd had socket activation enabled by default in RHEL-9, so issuing a command to multipathd automatically started it. This is no longer the case by default in RHEL-10. Either leapp needs to notify users of this change, or it needs to enable it (by uncommenting "WantedBy=sockets.target" in /lib/systemd/system/multipathd.socket
• managing multipathed NVMe devices with dm-mutipath is no longer supported in RHEL-10 (In RHEL-9, it was supported although it was not the default or the recommended method). If the user has dm-multipathed NVMe devices, upgrading will still work, but they should be notified that these devices will no longer be managed by dm-multipath. They will be managed by Native NVMe Multipathing.
• The getuid config option is no longer supported. There is no alternative for this in RHEL-10. If a rhel-9 config sets the getuid option it cannot be automatically upgraded to rhel-10.