You can look at the ingredients on both cans and compare.
It seems to me that you have #1 for 0-6 months and #2 for 7-12 months, etc.
In US, formula #1 is for the first year: 0-12 months and #2 is for the second year. Basically there's more calcium in #2 than in #1.
Actually, my bb's doctor said that they're pretty much the same and it's not necessary to switch to formula #2 and that's only marketing strategy of the formula manufacturers.
I think he might be right. How about for those breast-fed babies? The breastmilk from their moms is always still the same.