There is a bug on in the new iOS7 that even if your WiFi is working perfectly then also the error message mentioned below comes up and it does not matter how many times you tap that option of ‘Retry’ it will not download the application and it will rather keep popping the same message again and again. If you have been facing this problem then I have solution to it. Please follow the steps mentioned below.
Now most of the users prefer to download or update the applications on the WiFi network rather than doing the same on the cellular data because cellular data packs are way expensive that the WiFi Connection. The remedy to this is very simple. Try to update an application and whenever it shows this error message tap the option named ‘Done’.
Now go to the settings section and then switch on the cellular data and try to initiate the downloading of the application using the cellular data. Once the downloading starts, quickly go to the settings section again and then turn on the WiFi network (as the priority of the WiFi network is high it will take-over the cellular data and you will see that the icon of 3G will be replaced by WiFi icon).
After switching ON the WiFi, go ahead and switch OFF the cellular data to make sure that the Cellular data to make sure that downloading of the application is not utilizing any of the Cellular data. That’s it!! Now the update will be downloaded and installed on the WiFi network and if this problem happens again then I will suggest you to follow the same steps again. Restoring your iPhone will not be a solution because I have already tried that and it did not work.