I created a full archive of my documents yesterday, and today wanted to create an incremental archive of anything that's changed since yesterday, using the following command:
7z u backups\full-2014-05-04.7z.001 -u- -up0q3r2x2y2z0w2!update-2014-05-05.7z c:\users\me\documents
I've tried this in both the stable 9.20 version and the 9.32 alpha versions, and both report "System error: Not implemented".
After some searching I found that you can't update files in a multi-volume archive. But I'm not trying to do that, I'm just trying to make a new archive based on changes from the multi-volume source archive. Is that not supported? It seems like it should be, since the program only needs to read in the contents of the original archive, not make any changes. Am I doing something wrong?
That code is complicated.
Now I'm not ready to fix that bug.