diff --git a/.github/workflows/bundle-ucm.yaml b/.github/workflows/bundle-ucm.yaml
index bd05781b39..6724728982 100644
--- a/.github/workflows/bundle-ucm.yaml
+++ b/.github/workflows/bundle-ucm.yaml
@@ -40,7 +40,7 @@ jobs:
       - name: install stack
         uses: unisonweb/actions/stack/install@main
         with:
-          stack-version: 2.15.5
+          stack-version: 2.15.7
 
       - name: build
         run: |
diff --git a/.github/workflows/ci.yaml b/.github/workflows/ci.yaml
index d162852e92..ebc93c151f 100644
--- a/.github/workflows/ci.yaml
+++ b/.github/workflows/ci.yaml
@@ -110,7 +110,7 @@ jobs:
         if: steps.cache-ucm-binaries.outputs.cache-hit != 'true'
         uses: unisonweb/actions/stack/install@main
         with:
-          stack-version: 2.15.5
+          stack-version: 2.15.7
 
       # Build deps, then build local code. Splitting it into two steps just allows us to see how much time each step
       # takes.
diff --git a/.github/workflows/haddocks.yaml b/.github/workflows/haddocks.yaml
index 2fb12dad65..d9db7cca07 100644
--- a/.github/workflows/haddocks.yaml
+++ b/.github/workflows/haddocks.yaml
@@ -28,7 +28,7 @@ jobs:
       - name: install stack
         uses: unisonweb/actions/stack/install@main
         with:
-          stack-version: 2.15.5
+          stack-version: 2.15.7
 
       - name: build with haddocks
         working-directory: unison
diff --git a/.github/workflows/update-transcripts.yaml b/.github/workflows/update-transcripts.yaml
index 7b298656e9..22e9e95140 100644
--- a/.github/workflows/update-transcripts.yaml
+++ b/.github/workflows/update-transcripts.yaml
@@ -23,7 +23,7 @@ jobs:
       - name: install stack
         uses: unisonweb/actions/stack/install@main
         with:
-          stack-version: 2.15.5
+          stack-version: 2.15.7
 
       # One of the transcripts fails if the user's git name hasn't been set.
       - name: set git user info