Microsoft released an application that allows you to back-up your SMS on Windows Phone 8.1 to your SD card. Note that the application does not work at the moment for Windows Phones without a SD card.
- Download the ‘contacts+message backup‘ from the Windows Phone Store here.
- Open ‘Settings‘ application.
- Scroll to the bottom, and find ‘contacts+message backup’. On Windows Phone 8.1 GDR2 (Update 2), it can be found in the ‘extras‘ section.
Contacts will be backed up to the *.vcf file format. It can be used with various software on Android, iOS, Microsoft Outlook, Google Contacts and so on, …
Text messages are backed up to a XML format.