If your client sends you an Accountant's Copy from an earlier version of QuickBooks, you may not be able to use it.
You can open Accountant's Copy files created from either the same version of QuickBooks you use or from the previous year. For example, if you use QuickBooks 2012, you can open and update Accountant's Copy files created with either QuickBooks 2012 or 2011.
The file you send back to your client will be compatible with both QuickBooks 2012 and 2011. Be aware that what you can and can't do in an Accountant's Copy from a particular year is restricted to the way the features worked in that version of QuickBooks. Learn more about what you can and can't do in an Accountant's Copy.
Note: You can't convert an Accountant's Copy transfer file (.qbx) created in QuickBooks &lastyear; or later to a company file. You can convert the transfer file to a QuickBooks &thisyear; Accountant's Copy file (.qba) and then convert that file to a company file (.qbw).