I personally have never read that caveat, what is recommended is to always run the same version on components that use the same firmware bundle, in other words.... For a B series upgrade, you need the Infraestruture bundle (include firmware for Fabric Interconnects, IOMs and UCSM) and also need the Server bundle (which includes the firmware for the CIMC, BIOS and Adapter).
Bottom line, the recommendation is to run exactly the same version for components that use firmware that come from the same bundle BUT, UCSM 2.1 introduces an enhancement: "Mixed version support (for infra and server bundles firmware) " wich allows the combination of SOME infraestructure bundles with some server bundles.
Nice to see that table (I had not seen it), I wil free up some memory
According to the table, 2.0(5) server bundle is compatible with 2.1(3) Infrastructure bundle, if you understood it that way, you are 100% correct. <<< Thanks for sharing the link with ALL the compatible mix possibles.
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