How to disable Meeting countdown:
Change display to "Tabbed Mode"- Settings> Display>Full-Screen,>Layout>Tabbed
How to: remove the timer that's on the far right corner (Shown Below in the red box)
Tabbed Settings under Visibility>Right Status Bar> Disable Meeting Time (Shown Below) - Once Disabled the meeting timer shown above will longer appear.
Change display to "Flat Mode"- Settings> Display>Full-Screen,>Layout>Flat
How to: Remove Meeting End Warning (Shown Below)
Display > Docked > Show Meeting Timer is unchecked, there will be no timer shown on the dockbar (Shown Below)