Until today, every backtest reached back to the same day in early 2024 — and that window grew a little longer every week. From now on it has a fixed length instead: the two years leading up to a strategy's birth, rolling forward as the market does.
Every new strategy is now graded on a window of fixed length: two years, ending shortly before the strategy goes live. The start date is no longer pinned to early 2024 — as the market moves forward, the window moves with it. You still can't choose the dates, and that's still the point.
Three reasons. Grades stay current — a window pinned to 2024 would keep grading strategies on a market that drifts further into the past every month; two rolling years keep every grade about the market as it is now. Exams stay equal — a window that grows with the calendar would quietly hand different generations different tests; now every card, this year or next, sits an exam of exactly the same length. The shelf stays fresh — a moving window keeps changing the question the breeder has to answer, so it keeps surfacing genuinely new strategies instead of rediscovering the same answers to the same old test.
Cards born before this change keep their record exactly as it was — a backtest is frozen at creation, and nothing was re-scored. Their window was, if anything, longer: the same two years plus the history back to early 2024, judged by the same gates. Every card's report prints its exact test dates, and every card's Since Launch record is written on the same live candles as everyone else's.