Raspbian is based on Debian.
Debian generates three releases: stable, testing, unstable.
See https://www.debian.org/releases/
The "stable" distribution contains the latest officially released distribution of Debian.
The "testing" distribution contains packages that haven't been accepted into a "stable" release yet, but they are in the queue for that. The main advantage of using this distribution is that it has more recent versions of software.
The "unstable" distribution is where active development of Debian occurs. Generally, this distribution is run by developers and those who like to live on the edge.
Raspbian sort of tracks stable and testing. It does not have the equivalent of unstable.
jessie is the current testing. If jessie doesn't use the version you want you'll need to wait or build it from source.
it doesn't seem to get updated when I run my usual update command:
apt-get update && apt-get upgrade -y && apt-get dist-upgrade -y
If that's your usual update command, you've been led astray somewhere.
apt-get update will sync your local listings with the remote repos.
apt-get upgrade will upgrade all installed packages to the latest version in your local listings.
apt-get dist-upgrade is a prolonged process for updating the entire OS to the next version. Chances are you've already done this and currently you are just going through the motions with this command now. However, you may not have done it properly in the first place. If cat /etc/issue says "Raspbian GNU/Linux 7" (and not "8"), you did it wrong and have never actually upgraded.1
If it does say 8, you should have vsftpd 3.0.2-17.
1. Which might be sort of my fault if you followed the instructions here, since I didn't make it clear that you need to add a line to sources.list to both install jessie packages in wheezy and to upgrade from wheezy. I've clarified that now and those instructions should work.
