Personally, I would not worry much about what is on the box and start measuring if there is any change in accuracy.
The bullet is still the same - Sierra Match King.
I wasn't aware that they changed from IMR4064 powder, but I haven't been using factory ammo for years.
Anyone know what Federal chose to use after the change in powder?

As I remember from years ago, they also changed powders once before, I think when they changed from the buff and blue box to the maroon and gold box.
It didn't seem to make any difference in the measured accuracy then and if they are still committed to being the 'gold standard' for .308 ammo, they would be equally diligent.
Perhaps they changed from IMR4064 to a powder with less temperature sensitivity, like H4895, Varget, or IMR4166. That would be a very positive step.
From my reloads, those three powders perform very accurately in my .308s.