Software Currency

Software currency is the degree to which a system's runtimes, frameworks, and dependencies are current — running versions that are recent, supported, and patched. It is the positive framing of the same quantity that drift measures negatively: a highly current estate is one with low drift.

Why Teams Track It

Currency is a leading indicator. A current stack takes security patches the day they ship, upgrades in small steps instead of multi-quarter migrations, and gives AI assistants a stack that matches their training data more closely. A stale stack pays for the same upgrades later, at a higher price, on someone else's schedule — typically an end-of-life date or an actively exploited vulnerability.

Measuring It

Currency only improves when it is measured. A 0–100 DriftScore (lower is better) gives each project a currency number; portfolio views roll those numbers up so leadership can see whether the estate is modernizing or quietly rotting, and drift budgets in CI keep individual projects from sliding back.

Related Terms

Software currency is the inverse of drift, quantified by DriftScore, and defended with drift budgets and end-of-life tracking.