I originally asked this question on https://unix.stackexchange.com/, but I got no answers after 1 month, so please allow me to post it here on stakoverflow.
I used to be able to install php-5fpm=5.4.16-1~dotdeb.1, but it seems that this package is no longer available from the latest dotdeb packages.
Here are the steps I tried.
Append the following two lines in /etc/apt/sources.list.
deb http://packages.dotdeb.org wheezy all
deb-src http://packages.dotdeb.org wheezy all
Run apt-get update.
Run apt-get install php5-fpm=5.4.16-1~dotdeb.1.
However, this returns E: Version '5.4.16-1~dotdeb.1' for 'php5-fpm' was not found. I tried to avoid it by using a different respository, namely, deb http://packages.dotdeb.org wheezy-php54 all, but this returned the same message. How can I install that specific version of PHP?
You're targeting too specific a version. Repositories won't routinely keep multiple builds of the same package around, so a specific build like 5.4.16-1~dotdeb.1 will be superseded by newer builds.
At the moment, listing the files on the repository shows a build of 5.4.19-1~dotdeb.1, but really all you want is to select the latest version of PHP 5.4, and let APT update it in the normal way.
If the dotdeb packages are for newer versions of PHP than any other repositories you have installed, it will be the default anyway, so you can just run:
apt-get install php5-fpm