Follow the steps given below:
Download the latest version of Sublime Text 3 (at this time, it is Build-3126) as a
Install GDebi Package Installer (if not installed).
Then remove Sublime Text 3 (Build-3114) by opening its
.deb package(which you downloaded earlier) using GDebi Package Installer and then click on Remove Package.
Then open the
.deb package of the latest Sublime Text 3 version (probably, Build-3126) using GDebi Package Installer and click Install Package and install Sublime Text 3 Build-3126.
All your configurations (packages installed and other customisations) in Sublime Text 3 which you did earlier will be restored automatically even after following the above procedure. So you need not worry about installing the packages again. You will find those customisations and packages automatically in the latest version you have installed, because updating through this procedure doesn't remove/purge Sublime Text 3 configuration files.
This procedure works also for other code editors like Visual Studio Code and Atom. I have myself tested and verified it.
But you have to install Package Control again.
EDIT: Sublime Text 3.0 has been released. To install it in Ubuntu, use
apt package manager and run the commands given below one-by-one in terminal:
Install the GPG key:
wget -qO - https://download.sublimetext.com/sublimehq-pub.gpg | sudo apt-key add -
Select the channel to use:
echo "deb https://download.sublimetext.com/ apt/stable/" | sudo tee /etc/apt/sources.list.d/sublime-text.list
echo "deb https://download.sublimetext.com/ apt/dev/" | sudo tee /etc/apt/sources.list.d/sublime-text.list
Update apt sources and install Sublime Text
sudo apt-get update
sudo apt-get install sublime-text
Now whenever a Sublime Text update(after Sublime Text 3.0) will be available (depending on the channel you chose while installing Sublime Text), you can update it using Software Updater or by running the commands given below (one-by-one) in terminal:
sudo apt-get update
sudo apt-get upgrade