diff --git a/Dockerfile.angular b/Dockerfile.angular
index 4b5f2eb..c81e229 100644
--- a/Dockerfile.angular
+++ b/Dockerfile.angular
@@ -1,3 +1,3 @@
-FROM alpine:latest
+FROM alpine:3.15
 
 RUN apk add chromium openssh-client xvfb-run yarn zip
diff --git a/Dockerfile.arch b/Dockerfile.arch
index 06f04ee..9dc24cd 100644
--- a/Dockerfile.arch
+++ b/Dockerfile.arch
@@ -1,4 +1,4 @@
-FROM archlinux/base
+FROM archlinux:base-20220130.0.46058
 ENV LANG C.UTF-8
 
 RUN pacman -Syyu --noconfirm git python qt5-multimedia qt5-svg qt5-webengine qt5-webchannel qt5-tools python-pyqt5 \
diff --git a/Dockerfile.debian b/Dockerfile.debian
index 59daedb..fe22dce 100644
--- a/Dockerfile.debian
+++ b/Dockerfile.debian
@@ -1,4 +1,4 @@
-FROM debian:unstable
+FROM debian:11
 
 RUN apt-get update && DEBIAN_FRONTEND=noninteractive \
     apt-get install -y python3 qttools5-dev-tools pyqt5-dev-tools python3-pyqt5 python3-pyqt5.qtmultimedia \
diff --git a/Dockerfile.documentation b/Dockerfile.documentation
index 68eb97f..18feb44 100644
--- a/Dockerfile.documentation
+++ b/Dockerfile.documentation
@@ -1,3 +1,3 @@
-FROM alpine:latest
+FROM alpine:3.15
 
 RUN apk --no-cache add make py3-sphinx py3-sphinx_rtd_theme texlive-full
diff --git a/Dockerfile.fedora b/Dockerfile.fedora
index aa7fdea..5fef067 100644
--- a/Dockerfile.fedora
+++ b/Dockerfile.fedora
@@ -1,4 +1,4 @@
-FROM fedora
+FROM fedora:35
 
 RUN dnf install -y https://download1.rpmfusion.org/free/fedora/rpmfusion-free-release-$(rpm -E %fedora).noarch.rpm \
                    https://download1.rpmfusion.org/nonfree/fedora/rpmfusion-nonfree-release-$(rpm -E %fedora).noarch.rpm
diff --git a/Dockerfile.ubuntu b/Dockerfile.ubuntu
index dd4cc79..0904ff8 100644
--- a/Dockerfile.ubuntu
+++ b/Dockerfile.ubuntu
@@ -1,4 +1,4 @@
-FROM ubuntu:rolling
+FROM ubuntu:21.10
 
 RUN apt-get update && DEBIAN_FRONTEND=noninteractive \
     apt-get install -y python3 qttools5-dev-tools pyqt5-dev-tools python3-pyqt5 python3-pyqt5.qtmultimedia \
diff --git a/README.rst b/README.rst
index 8952b17..e06469c 100644
--- a/README.rst
+++ b/README.rst
@@ -2,3 +2,10 @@ OpenLP Docker Runners
 =====================
 
 This repository holds the configuration to build the Docker runners for testing OpenLP.
+
+
+.. note::
+
+   The Dockerfiles contain version numbers to uniquely identify the release we're using. This helps us keep track of
+   which version of software we're using, as well as allow for us to periodically update the software without resorting
+   to tricks to work around our build process.