My iPhone 4S broke and I was able to get my old 3GS up and running to use while waiting for repair parts to come in. The 3GS has been sitting in a drawer for a while and only has system 5.1. The phone is asking me if I want to upgrade to 6.1.3. I read some posts on forums from people who upgraded to that system and then couldn't use the 3G network or had battery issues. The threads I saw didn't seem to offer solutions to either problem. Is the risk of upgrading not as great as I think and should I go ahead and do the upgrade or just be happy with 5.1? If I do have battery or 3G problems, can they be fixed? I would like to upgrade if I can in case something else happens to my 4S again. AT&T won't offer me the cheap upgrade deal again until November. I also read somewhere that you could upgrade to older systems using the proper ISPW file and Tiny Umbrella. I tried to load 6.0.1 because it appears to be the latest bug-free OS. I followed some instructions which made it sound easy, but it didn't work and there were some scary moments when I didn't think I was going to be able to get my phone out of recover mode. I'm not interested in jail breaking the phone, I just want a more recent system since some of the apps I regularly use are no longer supported on iOS 5. Thanks for any help and info you can provide.