Binary compatibility

If i build VST plugins on Win7 with VS2008 (or VSExpress) will they work on Windows XP, and how much does that depend on how the host app is built. I’m getting some reports that VST plugins i’m releasing don’t work with Reaper on XP (standalone yes, with VC Redistributable Package installed) however the VSTs are not even listed.

Are there any build flags that i could change to make sure that plugins on windows vista xp and 7 ? I noticed that when i disable the “embed manifest” option it makes the app look for some completly different DLLs, what is that option ? what does it change.

Can optimization flags have impact on that ? Perhaps it’s that time that we need to supply builds for XP and Vista/7 seperate (i hope not).

If you build an application on Windows Xp, the application will run on Vista and Windows 7. I don’t know much about plug ins so can’t comment on it.