Series and continuity.

One continuous number, a fresh window twice a year. Windows run 12 months, and a new one opens every March and September, so two are live at once. Your pair belongs to its window from mint to settlement.

One number across many series.

The reference market launches a new series every six months, and old ones keep trading. You do not pick one.

Windows.

• A window opens each March and September and settles 12 months later, on the professional credit market roll dates.
• Only the newest window mints, so trading concentrates there.
• The prior window keeps trading through its final months, where settlement is close and the action concentrates. Exactly two windows are live at any time.
• Each window publishes its floor and cap before it opens, set by the published calibration rule and frozen at open.

The roll.

Nothing about your position rolls. When a new window opens, the old one keeps trading and merging until its own settlement; a holder who wants exposure to the new window sells one and buys the other, at market prices, whenever they choose. The continuity lives in the number: the administrator's methodology carries the reference market's series roll inside the official index, so settlement always reads one continuous published level.

Stated plainly.

There is no futures curve in v1: one number, one minting window, one book.