I've installed nginx 1.2.3 by adding a new ppa

sudo add-apt-repository ppa:nginx/stable
sudo apt-get update
sudo apt-get install nginx

However, nginx -v still gives me 1.1.19. What happened?

Output

The following packages will be upgraded:
  nginx
1 upgraded, 0 newly installed, 0 to remove and 46 not upgraded.
Need to get 61.8 kB of archives.
After this operation, 3,072 B of additional disk space will be used.
Get:1 http://ppa.launchpad.net/nginx/stable/ubuntu/ precise/main nginx all 1.2.3-0ubuntu0ppa3~precise [61.8 kB]
Fetched 61.8 kB in 0s (89.7 kB/s)
(Reading database ... 79914 files and directories currently installed.)
Preparing to replace nginx 1.1.19-1 (using .../nginx_1.2.3-0ubuntu0ppa3~precise_all.deb) ...
Unpacking replacement nginx ...
Setting up nginx (1.2.3-0ubuntu0ppa3~precise) ...

root@precise64:/var/www/apadment# nginx -v
nginx version: nginx/1.1.19