The mobile data cycle (Settings -> Data usage) looks quite arbitrary. Since I have changed my data plan, now the new cycle should start at the first day of the month instead of the 6th.
How can I change the begin of a data cycle? I cannot seem to find some edit button, though I vaguely remember seeing it at the Data usage cycle menu.
Affected versions: Android 4.0, 4.2.2, 4.3.1.