The legacy Web Client has been deprecated as of September 2019.
What does this mean?
Microsoft has set the 1st of October 2020 for when the Web Client will no longer be available. If you are still using the legacy Web Client, you will need to transition to the Unified Interface by this date.
Microsoft will still provide support, security and other critical updates to the Web Client until the 1st of October 2020.
There will be reminders and scheduling updates sent from Microsoft leading up to the cut off date.
It is now less than a year until the Web Client is deactivated, so make the change sooner than later!
The dates were referenced from: https://docs.microsoft.com/en-us/power-platform/important-changes-coming
If you want to know more about the Unified Interface, take a look at our blog “Why I Love the New Microsoft Dynamics 365 V9 Unified Interface and You will too”.
Also look at this blog on how to set the Unified Interface as default: