diff --git a/.github/workflows/CI.yml b/.github/workflows/CI.yml
index 06933dce..5039ca1c 100644
--- a/.github/workflows/CI.yml
+++ b/.github/workflows/CI.yml
@@ -28,8 +28,8 @@ jobs:
     # Use the Khronos container with the asciidoctor toolchain preinstalled.  We
     # reference the image by its SHA rather than its tag because they sometimes
     # overwrite a tag with a different image (which has a different SHA).  This
-    # SHA corresponds to tag "asciidoctor-spec.20240702".
-    container: khronosgroup/docker-images@sha256:4aab96a03ef292439c9bd0f972adfa29cdf838d0909b1cb4ec2a6d7b2d14a37f
+    # SHA corresponds to tag "asciidoctor-spec.20240727".
+    container: khronosgroup/docker-images@sha256:sha256:089687083ceb36483a3917389e4278718ab19c594099634f5dd80e22540c960f
 
     steps:
       # Checks-out your repository under $GITHUB_WORKSPACE, so your job can access it