iPhone claims diskspace is full
Although your device may show you that you have 1,5GB space available, it is possible that the free space notification is popping up due to application updates requiring a bit more space than that. Try resetting your settings (don't worry, you won't lose any data!) to see if that helps.


Open the "Settings" app.
Tap "General".
Scroll to the bottom and tap "Reset"
Tap "Reset All Settings". This will only reset settings to their factory defaults and can often clean out any corrupt preferences that may cause undesirable behaviour. Your data such as contacts, photos, apps etc will not be touched.
Enter your passcode (if you have one set)
Confirm that you wish to reset your settings.


When your device has restarted, check your free space again. It might have increased a little and you should no longer get the notification that you are running out of storage space.