This document analyzes technical lag in Docker images by quantifying outdated packages. The researchers extracted package data from 2,253 official Docker images and measured package time lag and version lag compared to latest available versions. They found most images contain outdated packages, with the degree of lag related to the Alpine Linux version used. While some images updated packages over time, overall the number of outdated packages in images increased. Technical lag can help assess image and repository health by identifying outdated dependencies.