[c-nsp] Catalyst IOS version skip - significant difference or just numbers game?

[Jeff Kell]

After checking some software revision data during the holiday break, I
noticed that the 29xx/35xx Catalyst IOS train has jumped 12.2(58)SE up
to 15.0(1)SE.

Is there really a significant difference, or is this just a marketing
numbers game to look more "current" ?

And if you've already made the leap, any gotchas?

Jeff