Works for me 3gs 4.1
I just tried this app w/out problem .. it is only limited to group feature that allow grouping contact on the phonebook (AS IT SAYS). +++It will create a group list on iphone official contacts or phonebook+++ ALTHOUGH THIS APP HAS LIMITATED FEATURES, I CANT COMPLAIN BCUZ THE IOS IPHONE DOES NOT HAVE SUCH GROUP FEATURE OR CAPABILITY TO ADD ON THE PHONE DESPITE GREAT IOS.
PS: I got tacts apps free and it does the same thing with more feature and customization.
Flavs83 about
Easy Groups, v1.3.2