My VS2005 solution contains Intel projects (i.e. .icproj).
In VS2010, attempting to load the solution brings up the 'solution conversion wizard', however the wizard attempts to convert the Intel .icproj too, and deals with the "Version" field as if it had Microsoft-style numbering.
To explain, a VS2005 project hasVersion="8.00". an Intel 11.1 project (.icproj) hasVersion="11.1". Now 11.1 isn't recognized by the wizard as a valid version, and so the conversion emits an error:
'11.1' violates enumeration constraint of '7.00 7,00 7.10 7,10 8.00 8,00 9.00 9,00'. The attribute 'Version' with value '11.1' failed to parse.
I suspect this is also causing the conversion wizard to reappear when reopening theallegedlyconverted solution.
IMO This depends on the task you want to achieve and a complexety of the project.
For example, in Intel TBB we support VS2005 as the oldest studio and all samples projects are based onVS2005 or Compiler 12.1. They all rely on compilers converters and work pretty well with some warnings for the latest studio.
Even if your team work in one studio on one big project you need to think that in a few years you need to upgrade the build to newer compiler version because of new bug fixes and new security and other features.