How to Install LibreOffice 5.3 in Ubuntu 16.04, 14.04

http://tipsonubuntu.com/2017/01/31/install-libreoffice-5-3-ubuntu

Although LibreOffice website offers official DEB binaries, the best way to install or upgrade to LibreOffice 5.3 in Ubuntu 16.10, Ubuntu 16.04, Ubuntu 14.04, and Linux Mint 17 & 18 is using the LibreOffice Fresh PPA.

Once the PPA updated with the new packages, follow the steps below to install it:
1. Open terminal (Ctrl+Alt+T) and run command to add the PPA:

sudo add-apt-repository ppa:libreoffice/ppa
Type in your password when it prompts and hit Enter.

2. After that, launch Software Updater (Update Manager) and after checking for updates you’ll see new release of LibreOffice packages available:

How to Downgrade

To uninstall the new LibreOffice release and downgrade to the original version available in Ubuntu main repository, open terminal and run command:

sudo apt-get install ppa-purge && sudo ppa-purge ppa:libreoffice/ppa