Problems installing postgresql-9.4: Unable to locate package

You can install postgres 9.4 on Ubuntu 14.04!

Follow the instructions on http://www.postgresql.org/download/linux/ubuntu/:

Create the file /etc/apt/sources.list.d/pgdg.list, and add a line for the repository:

deb http://apt.postgresql.org/pub/repos/apt/ trusty-pgdg main

Import the repository signing key, and update the package lists:

wget --quiet -O - https://www.postgresql.org/media/keys/ACCC4CF8.asc | \
  sudo apt-key add -
sudo apt-get update

Now you can install with

sudo apt-get install postgresql-9.4

That is because in Ubuntu 14.04 repositories there is postgresql-9.3 version. So run

sudo apt-get install postgresql-9.3