We have installed and configured NAV 2016 web client. Works fine.
However, it appears to be possible to simply change the company name element of the url and this by-passes NAV security.
Example:
Two NAV companies, Company A and Company B
User only has access to Company A as per NAV security permissions
URL for web client is
https://xxxxxxx/yyy/WebClient/?company=Company A but if user changes url to
https://xxxxxxx/DEV/WebClient/?company=Company B then then can access Company B, overriding security.
If they try to change company via 'My Settings' they (correctly) get an error.