move from nutch 0.71 to 0.8

[Insurance Squared Inc.]

I've seen it noted that a complete recrawl is necessary to migrate from 
0.71 to 0.8.  Is this absolutely necessary?  Or could a converter be 
created to migrate the data?  Has anyone created this? 

I expect at some point I'll have to move versions and something like 
this would be very useful.  If it's not been done yet and is possible, 
we'll likely tackle it at some point.