Converting of cache archives
If you change the filter settings, then these only have an effect on the pages which are loaded newly. Through this file names also can change. To adapt already stored pages in your cache archive to changed filter settings, these have to be converted.
You can use filters for the following purposes:
Joining two cache archives
You can join two cache archives together by indicating a cache archive as a source and a different one than target. All files which are only available in the source archive or are more newly than in the target archive are taken into the target archive.