the new sim will work with the i58 .the only problem is that you wont have your contact list. so if you can do without your contact list, then upgrade your sim. the only problem with using your old sim in your i730 is that you cant assing ringtones to contacts....its not too bad of a swap that way.

The Signal insurnace I have just sent me a new i730 to replace my broken i95 and I am told that I need to upgrade my all white SIM for a yellow SIM in order for my new phone to work right or it will void my insuance and warrenty Well, I put my original SIM card in the 730 and it seems to work just fine, so my question is, do I really need a new SIM? Also, I plan on getting an i58 to use at work only.I will just swapout the SIM when I want to use the other phone. If I have to upgrade to a new SIM for the i730, will that new SIM work in the i58 phone? What are my options here and what is the difference between all the SIM cards?