New Messages Options
Another place you'll find visual changes in iOS 8.3 vs iOS 8.2 is the messages app. Apple adds two helpful features that will help you avoid spam texts and to keep conversations organized.
Go to Settings -> Messages -> Filter Unknown Senders and Tap On. This will toggle the settings so that you can see contacts and text messages in one section and unknown senders in another area.
Apple also fixes issues with group messages splitting, issues deleting individual messages and some preview problems in messages. There is also an option to report junk messages right from the messages app when you get text or iMessage spam.