Microsoft previously provided a tool called BIDS for SQL2008. This was replaced in SQL2012 by SSDT-BI which is not to be confused with SSDT - it is a different tool. Versions of SSDT-BI have been provided for VS2012 and VS2013 that support SQL2008, SQL2012 and SQL2014. Microsoft state here that
"for SQL Server 2012 or 2014, you can use either SSDT-BI for Visual Studio 2012 or SSDT-BI for Visual Studio 2013. The only difference is between the two is the Visual Studio version"
For VS2015, Microsoft have provided SSDT which contains no BI tools as usual but they have also released SSDT Preview which does include BI tools. It looks like this is called "Preview" because it supports SQL2016 which has not yet been released. It also supports SQL Server versions from 2008 onwards. As stated here
SSDT is based on Visual Studio and co-released with SQL Server as a free web download.
Therefore it seems that the SSDT Preview for VS2015 may cease to be a preview once SQL2016 is released. Alternatively Microsoft may release SSDT for VS15 (someone at MS - please choose a naming convention) only as this could release at around the same time as SQL2016. It probably seems that I am nit-picking because the functionality I require is available in SSDT Preview for VS2015 but I am not permitted to use any software that is not fully supported by the supplier. I just want to use BI project templates in the latest release version of visual studio - surely this should be supported? Is it? Am I missing something?
Microsoft will release a GA (non-Preview) version of SSDT that contains the BI project templates. The GA version will be a seamless upgrade from the Preview version.