Since updating my iPhone 5S to 7.1, there is lag in launching apps. For example when i press an app, the icon darkens for a second and then launches. This problem did not exist before 7.1. I hoped for a fix with 7.1.1 but it has not been fixed. What i have noticed is that this lag happens when my iPhone is connected to cellular data. If i switch my phone to airplane mode, this lag disappears completely. I haven't found a fix yet. My iPad air on 7.1 is very fast and it's on wifi only. Did anyone else notice this problem? I hope someone can help.