diff --git a/ci/alpine/Dockerfile b/ci/alpine/Dockerfile
index 968771d5fb..9fda9d4a98 100644
--- a/ci/alpine/Dockerfile
+++ b/ci/alpine/Dockerfile
@@ -2,7 +2,7 @@ FROM alpine:latest
 
 # A version field to invalidate Cirrus's build cache when needed, as suggested in
 # https://github.com/cirruslabs/cirrus-ci-docs/issues/544#issuecomment-566066822
-ENV DOCKERFILE_VERSION 20250306
+ENV DOCKERFILE_VERSION=20250905
 
 RUN apk add --no-cache \
   bash \
diff --git a/ci/centos-stream-10/Dockerfile b/ci/centos-stream-10/Dockerfile
index 9c5e033346..a76fe1bc56 100644
--- a/ci/centos-stream-10/Dockerfile
+++ b/ci/centos-stream-10/Dockerfile
@@ -2,7 +2,7 @@ FROM quay.io/centos/centos:stream10
 
 # A version field to invalidate Cirrus's build cache when needed, as suggested in
 # https://github.com/cirruslabs/cirrus-ci-docs/issues/544#issuecomment-566066822
-ENV DOCKERFILE_VERSION 20250905
+ENV DOCKERFILE_VERSION=20250905
 
 # dnf config-manager isn't available at first, and
 # we need it to install the CRB repo below.
diff --git a/ci/centos-stream-9/Dockerfile b/ci/centos-stream-9/Dockerfile
index 0c0451f06c..bba69b6861 100644
--- a/ci/centos-stream-9/Dockerfile
+++ b/ci/centos-stream-9/Dockerfile
@@ -2,7 +2,7 @@ FROM quay.io/centos/centos:stream9
 
 # A version field to invalidate Cirrus's build cache when needed, as suggested in
 # https://github.com/cirruslabs/cirrus-ci-docs/issues/544#issuecomment-566066822
-ENV DOCKERFILE_VERSION 20241024
+ENV DOCKERFILE_VERSION=20250905
 
 # dnf config-manager isn't available at first, and
 # we need it to install the CRB repo below.
diff --git a/ci/debian-12/Dockerfile b/ci/debian-12/Dockerfile
index 63825702b4..5968aadcd2 100644
--- a/ci/debian-12/Dockerfile
+++ b/ci/debian-12/Dockerfile
@@ -4,7 +4,7 @@ ENV DEBIAN_FRONTEND="noninteractive" TZ="America/Los_Angeles"
 
 # A version field to invalidate Cirrus's build cache when needed, as suggested in
 # https://github.com/cirruslabs/cirrus-ci-docs/issues/544#issuecomment-566066822
-ENV DOCKERFILE_VERSION 20241024
+ENV DOCKERFILE_VERSION=20250905
 
 RUN apt-get update && apt-get -y install \
     bison \
diff --git a/ci/debian-13/Dockerfile b/ci/debian-13/Dockerfile
index a9bc9e8eea..91384c1c27 100644
--- a/ci/debian-13/Dockerfile
+++ b/ci/debian-13/Dockerfile
@@ -4,7 +4,7 @@ ENV DEBIAN_FRONTEND="noninteractive" TZ="America/Los_Angeles"
 
 # A version field to invalidate Cirrus's build cache when needed, as suggested in
 # https://github.com/cirruslabs/cirrus-ci-docs/issues/544#issuecomment-566066822
-ENV DOCKERFILE_VERSION 20250813
+ENV DOCKERFILE_VERSION=20250905
 
 RUN apt-get update && apt-get -y install \
     bison \
diff --git a/ci/fedora-41/Dockerfile b/ci/fedora-41/Dockerfile
index e3d737a562..589e58326d 100644
--- a/ci/fedora-41/Dockerfile
+++ b/ci/fedora-41/Dockerfile
@@ -2,7 +2,7 @@ FROM fedora:41
 
 # A version field to invalidate Cirrus's build cache when needed, as suggested in
 # https://github.com/cirruslabs/cirrus-ci-docs/issues/544#issuecomment-566066822
-ENV DOCKERFILE_VERSION 20250203
+ENV DOCKERFILE_VERSION=20250905
 
 RUN dnf -y install \
     bison \
diff --git a/ci/fedora-42/Dockerfile b/ci/fedora-42/Dockerfile
index 578f168b26..ba7b5c39de 100644
--- a/ci/fedora-42/Dockerfile
+++ b/ci/fedora-42/Dockerfile
@@ -2,7 +2,7 @@ FROM fedora:42
 
 # A version field to invalidate Cirrus's build cache when needed, as suggested in
 # https://github.com/cirruslabs/cirrus-ci-docs/issues/544#issuecomment-566066822
-ENV DOCKERFILE_VERSION 20250508
+ENV DOCKERFILE_VERSION=20250905
 
 RUN dnf -y install \
     bison \
diff --git a/ci/opensuse-leap-15.6/Dockerfile b/ci/opensuse-leap-15.6/Dockerfile
index c49670ab51..b3eaf087c7 100644
--- a/ci/opensuse-leap-15.6/Dockerfile
+++ b/ci/opensuse-leap-15.6/Dockerfile
@@ -2,7 +2,7 @@ FROM opensuse/leap:15.6
 
 # A version field to invalidate Cirrus's build cache when needed, as suggested in
 # https://github.com/cirruslabs/cirrus-ci-docs/issues/544#issuecomment-566066822
-ENV DOCKERFILE_VERSION 20241024
+ENV DOCKERFILE_VERSION=20250905
 
 RUN zypper addrepo https://download.opensuse.org/repositories/openSUSE:Leap:15.6:Update/standard/openSUSE:Leap:15.6:Update.repo \
  && zypper refresh \
diff --git a/ci/opensuse-tumbleweed/Dockerfile b/ci/opensuse-tumbleweed/Dockerfile
index c8a3a9af67..85c990c54d 100644
--- a/ci/opensuse-tumbleweed/Dockerfile
+++ b/ci/opensuse-tumbleweed/Dockerfile
@@ -2,7 +2,7 @@ FROM opensuse/tumbleweed
 
 # A version field to invalidate Cirrus's build cache when needed, as suggested in
 # https://github.com/cirruslabs/cirrus-ci-docs/issues/544#issuecomment-566066822
-ENV DOCKERFILE_VERSION 20250502
+ENV DOCKERFILE_VERSION=20250905
 
 # Remove the repo-openh264 repository, it caused intermittent issues
 # and we should not be needing any packages from it.
diff --git a/ci/ubuntu-22.04/Dockerfile b/ci/ubuntu-22.04/Dockerfile
index a34cf52619..bad8e4c5b9 100644
--- a/ci/ubuntu-22.04/Dockerfile
+++ b/ci/ubuntu-22.04/Dockerfile
@@ -4,7 +4,7 @@ ENV DEBIAN_FRONTEND="noninteractive" TZ="America/Los_Angeles"
 
 # A version field to invalidate Cirrus's build cache when needed, as suggested in
 # https://github.com/cirruslabs/cirrus-ci-docs/issues/544#issuecomment-566066822
-ENV DOCKERFILE_VERSION 20241024
+ENV DOCKERFILE_VERSION=20250905
 
 RUN apt-get update && apt-get -y install \
     bc \
diff --git a/ci/ubuntu-24.04/Dockerfile b/ci/ubuntu-24.04/Dockerfile
index b4df50fcfb..49977a6215 100644
--- a/ci/ubuntu-24.04/Dockerfile
+++ b/ci/ubuntu-24.04/Dockerfile
@@ -4,7 +4,7 @@ ENV DEBIAN_FRONTEND="noninteractive" TZ="America/Los_Angeles"
 
 # A version field to invalidate Cirrus's build cache when needed, as suggested in
 # https://github.com/cirruslabs/cirrus-ci-docs/issues/544#issuecomment-566066822
-ENV DOCKERFILE_VERSION=20250522
+ENV DOCKERFILE_VERSION=20250905
 
 RUN apt-get update && apt-get -y install \
     bc \
diff --git a/ci/ubuntu-25.04/Dockerfile b/ci/ubuntu-25.04/Dockerfile
index 7bec70c7b4..695f480b2b 100644
--- a/ci/ubuntu-25.04/Dockerfile
+++ b/ci/ubuntu-25.04/Dockerfile
@@ -4,7 +4,7 @@ ENV DEBIAN_FRONTEND="noninteractive" TZ="America/Los_Angeles"
 
 # A version field to invalidate Cirrus's build cache when needed, as suggested in
 # https://github.com/cirruslabs/cirrus-ci-docs/issues/544#issuecomment-566066822
-ENV DOCKERFILE_VERSION 20241115
+ENV DOCKERFILE_VERSION=20250905
 
 RUN apt-get update && apt-get -y install \
     bc \
diff --git a/ci/windows/Dockerfile b/ci/windows/Dockerfile
index d1cba59c27..e615732f7c 100644
--- a/ci/windows/Dockerfile
+++ b/ci/windows/Dockerfile
@@ -5,7 +5,7 @@ SHELL [ "powershell" ]
 
 # A version field to invalidatea Cirrus's build cache when needed, as suggested in
 # https://github.com/cirruslabs/cirrus-ci-docs/issues/544#issuecomment-566066822
-ENV DOCKERFILE_VERSION 20250528
+ENV DOCKERFILE_VERSION=20250905
 
 RUN Set-ExecutionPolicy Unrestricted -Force