Determining the version of Ferret used to create an index

Ruby Apps Ferret
1

Hello,

I keep getting “IndexError: index XXXXXX out of string” when I try to
use the index (with XXXXXX changing depending on what version of Ferret
I try to use to load the index). The data from which I created the index
has been lost, and I’m hoping to retrieve whatever I can out of the
index.

Is there a way I can determine from a file header or something which
version of Ferret was used to create the index so I can install the
correct gem?

Thanks!
Michael