general question about quilt patch handling

[Werner Detter <werner@aloah-from-hell.de>]

Hi everbody, 

short question by example: quilt series contains several patches, e.g.

1.patch
2.patch
3.patch
4.patch 

let's assume 3.patch which worked for some time but will be no longer functional
because the 3.patch uses a function which will not available in future versions 
of dependency software (like libnet-dns-perl). 

what's the recommendation here? 

a) delete 3.patch completly and create a new quilt patch for the fix
b) leave 3.patch untouched and just create a new one which fixes the changes
   from 3.patch? 
c) something else? 

Cheers,
Werner