In alt.os.linux.debian, Joern Bredereck uttered the immortal words:

> how can I find out why packages are being kept back from upgrade?
>
> fuchur:~# apt-get upgrade -u
> Reading Package Lists... Done
> Building Dependency Tree... Done
> The following packages have been kept back
> comerr-dev e2fsprogs imagemagick libmagick5 mysql-client mysql-server
> php5-mysql sysvinit
>
> I assume there are dependancy problems between conflicting apt-sources,
> but how can I resolv those conflicts?

There are several reasons why packages are kept back. The most common ones I
see in unstable are:

1. A package depends on a package that doesn't exist yet.
2. A package depends on a package version that doesn't exist yet.
3. A package's dependencies have changed a new package needs to be installed
and/or an old package needs to be removed.

For 1 and 2 you just have to wait for the Debian maintainers to sort it out.
"apt-get dist-upgrade" can help with 3 but be careful with it. Use the -s
switch to see exactly what APT wants to do first.

Which branch of Debian are you using? My unstable box reports no php5*
packages at all and there appear to be no problems with the others. If
you're using unofficial repositories then that could be another reason.

--
Andy.