From various articles I learnt Business Intelligence Studio for SQL Server 2012 is now called SQL Server Data Tools (SSDT), and is an addon for VS. There are versions for VS 2010 and 2012, which can be downloaded from here.
What's the scope of backwards compatibility, i.e. can I use SSDT to develop reports for prior versions of SQL server? I am specifically interested in 2005 and above.
According to this article, SSDT should support 2005 and up, but for VS 2010. What's the level of this support - do projects needs conversion? Also, does the same apply for 2012 SSDT?
Would be nice if we could avoid installing several versions of Visual Studio per developer, just for the sake of report development for old clients.
SSDT supports 2005 and up, but both solution and project need conversion. I was able to convert 2005 solution and a 2008 R2 solution to VS 2010 (v10). You may choose to only convert the solution, and do not save converted project, to maintain compatibility with prior version of BIDS. So other developers will just keep using the project file, during the transition phase. However, with this setup, BIDS will keep asking to upgrade the project every time you start it, so it's a trade off.
Official support is there only for 2008 and up, because if you attempt to Detect Version of your SSRS, it will fail on 2005. So it can target 2008 and 2008 R2+, but still, you can generate reports for 2005 using 2008 target. And because format of RDL files does not change during conversion, I am assuming you can successfully develop and deploy reports to SSRS 2005 using this approach (at your own risk).