As long as all you need to calculate is the date, it's
straightforward:

{ = { DATE \@ "yyyy" } + 1 }

To insert each pair of field delimiters, press Ctrl+F9. Type the
instructions exactly as shown. Press F9 to update.

Note that the above fields show the next year based on the current
year. That is, if the field is updated next year, it will display
2008. If you want to add 1 to the creation date of the file, use the
following instead:

{ = { CREATEDATE \@ "yyyy" } + 1 }

{DATE \@ "yyyy"} will give you the year. (CTRL+F9 for the field boundaries)
{={DATE \@ "yyyy"} +1} will give you the year + 1
If you want anything more complicated you will have to sharpen that IQ.