My solution is a variation of this line in powershell, this example adds 1 year to the "Last Modified" time stamp of the files after the fact. Increase as the years go on... ie set 2013 with the correct month/day on the flip, then use the script command to add +10 years:
Get-ChildItem | select fullname,lastwritetime,@{n='NewLastWriteTime';e={($.LastWriteTime).addyears(10)}} | foreach {(gci $.fullname).LastWriteTime = $_.NewLastWriteTime}