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The 2016 program will allow you to open 2016 T2 files or carry forward 2015 T2 files to create a new 2016 T2 to complete for the 2016 tax year. The 2015 T2 will only open, for review or adjustment, in the 2015 version of TurboTax.
The file extension for the 2015 TurboTax T2 is .GB5 and 2016 is .GB6. So, each year TurboTax Business Inc has one file type it can open and one file type it can carry forward.
Hope this helps