The document discusses the concept of technical lag in software, which measures the difference between deployed software packages and their ideal counterparts, highlighting its significance in various contexts such as software deployment and package dependency management. It describes different metrics for measuring technical lag, including time, version, bugs, and vulnerabilities, and emphasizes the need for these metrics to be part of broader assessment tools for software health. The document also outlines open challenges and proposes new CHAOSS project metrics to measure software dependencies and their health.