diff --git a/.github/workflows/nix-build-and-upload.yaml b/.github/workflows/nix-build-and-upload.yaml
index 5bfce1b4..9ad63b27 100644
--- a/.github/workflows/nix-build-and-upload.yaml
+++ b/.github/workflows/nix-build-and-upload.yaml
@@ -9,10 +9,10 @@ on:
 jobs:
   x86_64-darwin:
     name: Build p4-fusion x86_64-darwin
-    runs-on: macos-latest
+    runs-on: macos-15-intel
     steps:
       - uses: actions/checkout@v4
-      - uses: DeterminateSystems/nix-installer-action@v8
+      - uses: DeterminateSystems/nix-installer-action@v22
       - name: '🔓 Authenticate to Google Cloud'
         uses: google-github-actions/auth@v1
         with:
@@ -45,7 +45,7 @@ jobs:
     runs-on: macos-latest-xlarge
     steps:
       - uses: actions/checkout@v4
-      - uses: DeterminateSystems/nix-installer-action@main
+      - uses: DeterminateSystems/nix-installer-action@v22
       - name: '🔓 Authenticate to Google Cloud'
         uses: google-github-actions/auth@v1
         with:
@@ -78,7 +78,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
-      - uses: DeterminateSystems/nix-installer-action@main
+      - uses: DeterminateSystems/nix-installer-action@v22
       - name: '🔓 Authenticate to Google Cloud'
         uses: google-github-actions/auth@v1
         with:
diff --git a/.github/workflows/pr-auditor.yaml b/.github/workflows/pr-auditor.yaml
index 66dfdfac..d11c63c1 100644
--- a/.github/workflows/pr-auditor.yaml
+++ b/.github/workflows/pr-auditor.yaml
@@ -23,5 +23,5 @@ jobs:
   report_failure:
     needs: check-pr
     if: ${{ failure() }}
-    uses: sourcegraph/sourcegraph/.github/workflows/report-job-failure.yml@main
+    uses: sourcegraph/workflows/.github/workflows/report-job-failure.yml@main
     secrets: inherit
diff --git a/.github/workflows/validate-migration.yaml b/.github/workflows/validate-migration.yaml
index f8878ab6..95288466 100644
--- a/.github/workflows/validate-migration.yaml
+++ b/.github/workflows/validate-migration.yaml
@@ -26,8 +26,8 @@ env:
   P4USER: "admin" # the name of the Perforce user
   P4PASSWD: ${{ secrets.P4PASSWD }} # the ticket for the Perforce user
 
-  # Setup: Enable sccache for faster builds
-  SCCACHE_GHA_ENABLED: "true"
+  # Setup: Enable local sccache for faster builds. Do not make compilation
+  # depend on the availability of GitHub's remote artifact cache.
   CMAKE_C_COMPILER_LAUNCHER: "sccache"
   CMAKE_CXX_COMPILER_LAUNCHER: "sccache"
 
@@ -42,6 +42,9 @@ jobs:
   validate-migration:
     strategy:
       fail-fast: false
+      # The shared Perforce server only has two client license slots available
+      # for validation jobs.
+      max-parallel: 2
       matrix:
         tool: # Note: If you add or change the name of tools here, you must also adjust the logic in the "Prepare environment for specific tool" step
           - addressAndUndefinedSanitizer # https://github.com/google/sanitizers/wiki/AddressSanitizer and https://clang.llvm.org/docs/UndefinedBehaviorSanitizer.html
@@ -166,9 +169,7 @@ jobs:
       - uses: actions/checkout@v2
 
       - name: "Run sccache"
-        uses: mozilla-actions/sccache-action@v0.0.3
-        with:
-          version: "v0.6.0"
+        uses: mozilla-actions/sccache-action@v0.0.10
 
       - name: "Install Perforce CLI"
         uses: perforce/setup-p4@1.0.2
diff --git a/nix/helix-core-api.nix b/nix/helix-core-api.nix
index 8b01afe8..a7395eec 100644
--- a/nix/helix-core-api.nix
+++ b/nix/helix-core-api.nix
@@ -4,17 +4,17 @@
     aarch64-darwin = fetchzip {
       name = "helix-core-api";
       url = "https://filehost.perforce.com/perforce/r23.1/bin.macosx12arm64/p4api-openssl1.1.1.tgz";
-      hash = "sha256-3j3WnBdfTa9job+w8mzcAltO8wgbMlxA/aJxWlLn/Dk=";
+      hash = "sha256-oUzpbJhcDEgJ5gxQ2dHZ/M2hhWTj0p4Pv9iL6GOvCXY=";
     };
     x86_64-darwin = fetchzip {
       name = "helix-core-api";
       url = "https://filehost.perforce.com/perforce/r23.1/bin.macosx12x86_64/p4api-openssl1.1.1.tgz";
-      hash = "sha256-go7uhe6eAX+rnnn5zzmKPya93ZK65q6bL0nsDXLx0ZA=";
+      hash = "sha256-1HQXcF/3lRv5H2L2IKvWNyYYY6myTOSTttIl46UBTfY=";
     };
     x86_64-linux = fetchzip {
       name = "helix-core-api";
       url = "https://filehost.perforce.com/perforce/r23.1/bin.linux26x86_64/p4api-glibc2.3-openssl1.1.1.tgz";
-      hash = "sha256-8Nv2xbXEYrheS930zyozSqMuC7X2V81IWW2woD/jqB4=";
+      hash = "sha256-891vpiR0Ni3ntdHvsQ4hviS/et2YKDBgIg3bGQ0xFI0=";
     };
   };
   "3.0" = {