Question: Which is the latest version of ubuntu operating system?

Disambiguated questions and answers:
context: The first point release, 16.04.1, was released on 21 July 2016. Release of Ubuntu 16.04.2 was delayed a number of times, but it was eventually released on 17 February 2017. Ubuntu 16.04.3 was released on 3 August 2017. Ubuntu 16.04.4 was delayed from 15 February 2018 and released on 1 March 2018, providing the latest Linux kernel, 4.13, from Ubuntu 17.10. Ubuntu 16.04.5 was released on 2 August 2018, and Ubuntu 16.04.6 was released on 28 February 2019.
question: Which is the latest version of ubuntu operating system as of 19 October 2017?
short_answers: Ubuntu 17.10

17.10

Artful Aardvark
wikipage: Ubuntu version history

context: On 17 October 2016, Mark Shuttleworth announced that the codename of Ubuntu 17.04, released on 13 April 2017, would be "Zesty Zapus".
question: Which is the latest version of ubuntu operating system as of 13 April 2017?
short_answers: Zesty Zapus

Ubuntu 17.04

17.04
wikipage: Ubuntu version history

context: Mark Shuttleworth announced on 21 April 2016 that Ubuntu 16.10 would be called "Yakkety Yak". It was released on 13 October 2016.
question: Which is the latest version of ubuntu operating system as of 13 October 2016?
short_answers: Ubuntu 16.10

Yakkety Yak

16.10
wikipage: Ubuntu version history

context: No context provided
question: What is the Unbutu OS version released on 2017-10-19?
short_answers: Artful Aardvark

17.10

context: No context provided
question: What is the Unbutu OS version released on 2017-04-13?
short_answers: Zesty Zapus

17.04

context: No context provided
question: What is the Unbutu OS version released on 2016-10-13?
short_answers: Yakkety Yak

16.10

Long answers:
knowledge: content: Mark Shuttleworth announced on 21 April 2016 that Ubuntu 16.10 would be called Yakkety Yak.[268] It was released on 13 October 2016.[269]
On 17 October 2016, Mark Shuttleworth announced that the codename of Ubuntu 17.04, released on 13 April 2017, would be Zesty Zapus.[275]
The name of this release, Artful Aardvark, was announced via Launchpad on 21 April 2017, instead of on Shuttleworth's blog as had been the case in the past. It was released on 19 October 2017.[279][280][281]
wikipage: Ubuntu version history Ubuntu 16.10 (Yakkety Yak)
long_answer: Mark Shuttleworth announced on 21 April 2016 that Ubuntu 16.10 would be called Yakkety Yak. It was released on 13 October 2016. On 17 October 2016, Mark Shuttleworth announced that the codename of Ubuntu 17.04, released on 13 April 2017, would be Zesty Zapus.  The name of the next release, Artful Aardvark, was announced via Launchpad on 21 April 2017, instead of on Shuttleworth's blog as had been the case in the past. It was released on 19 October 2017. 

knowledge: content: Ubuntu (/ʊˈbʊntuː/ (About this soundlisten) uu-BUUN-too)[7] is a Linux distribution based on Debian and composed mostly of free and open-source software.[8][9][10]
wikipage: Ubuntu
long_answer: Ubuntu is a Linux distribution based on Debian and composed mostly of free and open-source software. On October 13, 2016, a version called Yakkety Yak, Ubuntu 16.10, was released. Ubuntu 17.04, released on 13 April 2017, would be Zesty Zapus. On October 19, 2017, Ubuntu 17.10, known as Artful Aardvark, was released.