Because the website is built with Joomla! 3 cms it is possible to keep the content of the 'old' version of a website and provide it with a completely new design.
The content and presentation are completely separate from each other and therefore it is possible to provide a website with a completely new template that meets the latest requirements, such as a full-responsive layout.
This saves a lot of time when upgrading a website to the latest requirements you put on a modern website in order to reach the largest possible number of visitors.