I just noticed that the managed driver is now out of beta. Since I'd really like to modify my application to use the managed driver I read a few parts of the updated documentation. There I found the following on the system requirements page (http://docs.oracle.com/cd/E16655_01/win.121/e17732/InstallSystemRequirements.htm#i1006191):
Oracle Data Provider for .NET, Unmanaged Driver requires the following:
32-bit: Windows 7 (Professional, Enterprise, and Ultimate Editions), Windows Server 2008 (Standard, Enterprise, Datacenter, Web, and Foundation Editions), or Windows 8 (Pro and Enterprise Editions).
64-bit: Windows 7 x64 (Professional, Enterprise, and Ultimate Editions), Windows Server 2008 R2 x64 (Standard, Enterprise, Datacenter, Web, and Foundation Editions), Windows Server 2008 x64 (Standard, Enterprise, Datacenter, Web, and Foundation Editions), Windows 8 (Pro and Enterprise Editions), or Windows Server 2012 x64 (Standard, Datacenter, Essentials, and Foundation Editions).
Oracle Data Provider for .NET, Managed Driver requires the following:
Same Windows operating system support as ODP.NET, Unmanaged Driver.
Microsoft .NET Framework 4 or later
Is this really true? Why does a fully managed .NET assembly that is build for .NET 4.0 not support Windows XP and Windows Vista? Even .NET 4.5 still supports Windows Vista!
The beta and production OS requirements have remained the same for the managed provider. Windows 7 was the earliest client OS Oracle supported for managed ODP.NET.
At a theoretical level, managed ODP.NET can run on any OS that .NET 4 can run on. At a practical level, platform combinations need to be tested and certified to ensure they are in proper working order. As testing resources are finite, a choice needs to be made to test on all currently supported OSes or focus on the most popular ones. In the former case, you spread your testing out more thinly. In the latter, you can focus your energies more on the popular OSes to ensure higher quality running on those OSes. Since most OS industry analysts expect Windows XP and Vista to quickly recede in market share compared to Windows 7 and 8.x, the best choice appeared to focus on Windows 7 and higher.
XP will reach Microsoft's end of life middle next year. Very few business users will adopt it for the next iteration of ODP.NET apps.
Vista has low popularity, already below 5% in the overall Windows OS share and quickly declining. In the business community, most jumped from XP to 7, skipping Vista. The Vista market share among business users is much likely even lower as the 5% number also includes consumers.