Edit: Due to the fact that this article is old, the installation instructions may not work anymore. In order to successfully install the latest version of Wireshark, please access the wireshark tag and open the latest article (the one on top).
As you already know, Wireshark is an open-source protocol analyzer software, very used for monitoring the network traffic.
The latest version available is Wireshark 2.6.4 which has been recently released, bringing many changes.
The full list of changes is available here.
Up to date packages are available via the Wireshark PPA, so installing the software on Ubuntu should not cause problems to anyone.
All you need to do is add the PPA to your system, update the local repository index and install the wireshark package:
$ sudo add-apt-repository ppa:wireshark-dev/stable
$ sudo apt-get update
$ sudo apt-get install wireshark
Optional, to remove wireshark, do:
$ sudo apt-get remove wireshark
The installation instructions work on Ubuntu 18.04 Bionic Beaver, Ubuntu 16.04 Xenial Xerus and other Ubuntu derivative systems, like Linux Mint and Elementary OS.