Apple iOS 8.2 (build number 12D508) has now been released. This is a major release, the largest since iOS 8 was released and contains many bug fixes and is available for iPhones, iPads and iPod touches. To download this update you will need to use iTunes or WiFi. The update on my iPhone 6 that was on version 8.1.3 was 476MB.
Before running the update I recommend that you backup your device including any purchases and then once the update has run I always perform a hard reset and check for any updates to applications in the App Store.
Below is the iOS Official 8.2 change log that was released by Apple.
Apple Watch support
New Apple Watch app to pair and sync with iPhone, and to customize Watch settings
New Activity App for viewing fitness data and achievements from Apple Watch; appears when Apple Watch is paired
Available on iPhone 5 and later
Health App improvements
Adds the ability to select the unit of measurement for body temperature, weight, height, distance, and blood glucose
Improves stability when dealing with large amounts of data
Includes the ability to add and visualise workout sessions from 3rd-party apps
Addresses an issue that may have prevented users from adding a photo in Medical ID
Fixes units for vitamins and minerals
Fixes an issue where Health data wouldn’t refresh after changes data source order
Fixes an issue where some graphics showed no data values
Adds a privacy setting that enables turning off tracking of steps, distance, and flights climbed
Increases stability of Mail
Improves stability of Flyover in Maps
Improves stability of Music
Improves VoiceOver reliability
Improves connectivity with Made for iPhone Hearing Aids
Fixes an issue in Maps that prevented navigating to some favorite locations
Addresses an issue where the last word in a quick reply message wasn’t autocorrected
Fixes an issue where duplicate iTunes purchased content could prevent iCloud restore from completing
Resolves an issue where some music or playlists didn’t sync from iTunes to the Music app
Fixes an issue where deleted audiobooks sometimes remained on the device
Resolves an issue that could prevent call audio from routing to car speakers while using Siri Eyes Free
Fixes a Bluetooth calling issue where no audio is heard until the call is answered
Fixes a timezone issue where Calendar events appear in GMT
Addresses an issue that caused certain events in a custom reoccurring meeting to drop from Exchange calendar
Fixes an certificate error that prevented configuring an Exchange account behind a third-party gateway
Fixes an issue that could cause an organizer’s Exchange meeting notes to be overwritten
Resolves an issue that prevented some Calendar events from automatically showing as “busy” after accepting an invite.