This morning, Microsoft published a partial changelog for Windows Phone 8.1 Update 1. The listing is incomplete because it misses things like Cortana's Bluetooth integration or the new Store Live Tile. However, one area it did get right is the ability to select multiple entries on messaging, contacts and even phone calls.
Previously, in Windows Phone 8.1 and below, users could either delete everything in the call-history or delete one by one. This approach lacks the granularity that many users desire, so the ability to bring up the familiar multiple-select check boxes goes a long way to improving control over one's content.