XenForo has only one phrase that contains just a word 'upgrade' and this phrase is used widely in ACP. There it has 2 meanings: An actual software upgrade (in addons) User promotion In Russian this phrase can't be translated to suit both meanings. I suggest developers so separate these two meanings into 2 parts. The one with software upgrade and another with user promotion.
We actually already have specific phrases for "upgrade add-on" and "upgrade user", though it looks like the potential area that's a problem really means "upgrade name", so I'll make a change to that effect.
The main problem is the promoted users list in ACP. One column has a title 'upgrade', which I think should be changed to 'Upgrade option' or to something similar.