Starting with Windows Phone 8, its possible to have all your SMS backed up to the cloud which can be restored later if you switch to a new phone or perform a reset. This was a pretty good move from Microsoft as it was one of the demanded features at User Voice.
On October 31st 2012, the same thread named as SMS Access API was changed to Under Review as there is no developer API which third party can use to export or import SMS from the device. Along with that a comment by the Cliff Simpkins (Sr Product Manager, Windows Phone Developer) was posted as below :
With the WP8 release, the team did add the capability for consumers to have the device backup texts (which has been added within the WP8 OS), but the platform still doesn’t have an API to do this.
As such, I’m marking this as ‘Under Review’. The team is aware of the ask and it is something that is being considered.
The last statement is pretty crucial as it says “It is something that is being considered” which may very well mean that Windows Phone Team might consider opening up the API in some way for developers to take advantage and come with even more functionality.
Since this is under consideration only, but it does gives us some positive sign that may be, just may be in the future or in the next update, this API becomes publicly available. Keeping fingers crossed.