Hi all. I have a very confusing problem that I have never encountered in all the phones I have had, I have a Samsung Galaxy S4 I9505 International version on Vodafone. I did not buy this phone from new but have never experienced any problems picking up signal etc. However when I checked the IMEI of the phone it says 'waiting for activation' or comes up as invalid on other places. Like I said I have experienced no difficulties in the 6 months of having this phone but i would like to know why I could be getting these messages if anyone could help? Even my carrier could not give me an answer :/