Previously, Microsoft had told developers interested in Office programmability, which refers to extending the Microsoft Office platform with custom code and third-party add-on applications, to use Visual Basic for Applications (VBA) and Visual Studio Tools for Office (VSTO).
It's unlikely that Microsoft will retire VBA, VSTO, or any other existing Office programmability tools anytime soon. That being said, we wouldn't be surprised if the company phased them out one day.
We can only hope that the software giant will offer its short term and long term plans for Office programmability, assuming this new approach is made official with an upcoming announcement. We can't expect Redmond to be too specific, but hopefully it will clear up the potential confusion we're predicting will occur amongst developers.
Right now, we barely have a glimpse of what's coming in Office 15. The good news is that Microsoft is getting ready to share a bit more about Microsoft Office 2010's successor. In fact, an official announcement is coming before the end of the year, so hold tight!