You'll find an important update waiting on your OnePlus One, if you haven't installed it yet: Cyanogen OS 13.1. The OS' latest version is "MOD ready," which means the manufacturer can tweak parts of the Android-based platform it couldn't before. In fact, version 13.1 already comes with the "mods" Cyanogen introduced in February, which mostly insert Microsoft features into various parts of the software. For instance, you can now make Skype calls straight from the device's Phone app and use OneNote to take notes within the Email and Phone applications.
If you're in the US, Cortana for OnePlus One can take hands-free selfies if you tell it to. It can also set reminders and access your sched with voice commands without having to unlock your device. Microsoft took the chance to bring its Hyperlapse technology to the phone, as well, giving its camera app the capability to capture stable time-lapse videos.
The only non-Microsoft mod of the bunch shows trending tweets right on your lock screen. But you don't have to worry about random people seeing them on your phone -- you'd have to manually activate both Twitter and Cortana lock screen mods via Settings. If you'd rather not make them accessible, simply leave them off. You can watch a video of the new features below to get a better feel of how they work and how they're integrated into the platform's apps.