7K is just a selling term, you need to use the regular documentation, for this, either do the jump upgrade, then upgrade to 10, or use PCD. You can also go to at least 8.0(2), then DRS restore on the UCS and keep upgrading.
PCD or jump upgrade would require you to upgrade to a compatible release before anything else.
You also need to review the RNs, new and changed docs, and upgrade guides for whatever path you take. All the information is available at cisco.com and on plenty of previous threads at CSC on how to upgrade.
Are you getting this error “Installer User Interface Mode Not Supported. The installer cannot run in this UI mode. To specify the interface mode, use the -i command-line option, followed by the UI mode identifier. The value UI mode identifiers...
The below trick might come handy when you have to add a new node to a cluster but you don't have or is unsure of the security password for the publisher. This procedure has been around for ages.
1) Login into the CLI of the Publisher.