Docker Engine 514 used year-month versions until 20.10 (December 2020); since 23.0 (February 2023) it uses major.minor.patch, where a major release may remove deprecated features and patch releases stay backward compatible. 29.0.0 arrived on 10 November 2025, making the containerd 234,762 image store the default; minor releases then came roughly monthly, up to 29.8.0 on 3 September 2026 and the patch 29.8.1 on 15 September, the version in this chapter. Docker 514 publishes a stable channel and a test channel for pre-releases, and keeps every stable build available:
apt-cache madison docker-ce | awk '{print $3}' | head -2
apt-cache madison docker-ce | awk 'END {print NR " versions, oldest " $3}'5:29.8.1-1~ubuntu.26.04~resolute 5:29.8.0-1~ubuntu.26.04~resolute 18 versions, oldest 5:29.3.1-1~ubuntu.26.04~resolute
The string is epoch 5:, upstream version, package revision and target release (resolute is 26.04). To pin a build server, install an exact string (sudo apt install docker-ce=5:29.8.1-1~ubuntu.26.04~resolute ...) and run sudo apt-mark hold docker-ce docker-ce-cli so a routine upgrade cannot move it. Compose 514 and Buildx 4,514 are versioned and released separately.