Following the release of a limited beta in November, Microsoft officially launched its digital personal assistant, Cortana, on iOS in December. Cortana can be used on iPhones running iOS 8 or above in the US and China, and Microsoft has now pushed an update to its assistant on those devices, bumping its version number up to 1.4.0.
Our esteemed former colleague, Brad Sams, was among those to spot the rollout of the update on his iPhone. The release notes include an overview of the improvements included in this latest update:

1. A Today View. For a quick glance at your reminders.
2. Support for 3D touch menu in iPhone 6S and iPhone 6S +.
3. A new monthly reminder feature and improved refresh mechanism.
4. Reduced app load time.
5. A better loading experience for low speed and unstable network conditions.
6. More stable voice interactions.

Alongside its release on iOS at the end of last year, Microsoft also made Cortana available on Android devices in the US and China running OS version 4.1.2 Jelly Bean or above. Cortana is being 'deeply integrated' into the Android-based Cyanogen OS too; the OnePlus One became the first device to get access to that functionality a month ago.
Source: @bdsams