v4 measures how active the market is right now against what is normal for this time of day — one 0–100 reading that means the same thing on every market and timeframe. It sizes the move; it does not time the trade.
Activity is measured against what is normal for this time of day — a busy open no longer reads as a spike on its own. Settles at bar close; never repaints.
The move size price has stayed inside most of the time from here. Size stops and targets against it — in points, ticks, currency or percent.
Quiet, Normal, Active, Extreme — with alerts for each state, one for activity easing off an extreme, and one for a sharp one-off move.
Day travel used, session range so far, typical bar size, move type, and how long the current state has held — at a glance.