Due to a change in the vthunk handling code in libc6 and libg++, you must upgrade to at least libg++272_2.7.2.8-0.1 when upgrading libc6.
The e2fsck program in e2fsprogs_1.10-4 has a bug in it which will cause it to destroy data on partitions above 2GB in size. The version in e2fsprogs_1.10-7 has fixed this bug. IMPORTANT: If you run the older libc6-based e2fsck on a 2 GB or greater partition, YOU WILL LOSE DATA.
Note also that both the man-db and the libc6-dev packages currently include
/usr/bin/gencat. The version of gencat in libc6-dev has been
reported to cause segfault problems with man-db, you may wish to reinstall
man-db after libc6-dev if you experience these problems.
Handling of NIS/YP has changed slightly with libc6. If you are using NIS,
you will probably need to change /etc/nsswitch.conf, the compat
option will preserve the libc5 behavior. You should also change the
networks line from files dns to files. This will prevent
network configuation programs from attempting to resolve hostnames.
The directory structure of the ftp site has been slightly modified, placing the contrib and non-free sections of the archive alongside the main section, to avoid contrib and non-free getting out of sync with earlier portions of the archives. You must have dpkg-ftp_1.4.9 or greater to update your machine using dpkg-ftp. If you are updating your machine via ftp, the proper information to give dpkg-ftp is:
/debiandists/unstable/main dists/unstable/non-free dists/unstable/contribDebian 1.3.1r4 included an update to libc5 which conflicts with libc6. The conflict was added because of problems with locales and the format of the utmp/wtmp files. An older version of libc5 which doesn't conflict, as well as the development librarys, is saved at ftp://ftp.gate.net/pub/users/storm/.