diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
index 6bc80f8..be95083 100644
--- a/.github/workflows/release.yml
+++ b/.github/workflows/release.yml
@@ -166,32 +166,39 @@ jobs:
       fail-fast: false
       matrix:
         # Matlab actions support limited OS versions, check availability.
-        # macOS is pinned to macos-14 (arm64) because the macos-latest image
-        # ships an Xcode too new for R2024b's mex linker.
-        os: [ubuntu-latest, windows-latest, macos-14]
+        # macOS uses macos-15 (arm64), whose images ship only Xcode 16 and
+        # newer. R2024b's mex linker needs Xcode 15, so macOS builds with
+        # R2025a, which supports Xcode 16. Linux and Windows stay on R2024b.
+        include:
+          - os: ubuntu-latest
+            matlab: R2024b
+          - os: windows-latest
+            matlab: R2024b
+          - os: macos-15
+            matlab: R2025a
     steps:
       - uses: actions/checkout@v4
 
       - uses: matlab-actions/setup-matlab@v2
         with:
-          release: 'R2024b'
+          release: ${{ matrix.matlab }}
 
-      # MATLAB R2024b's mex linker is incompatible with the very new Xcode on
-      # the default image, so select a supported Xcode 15.x.
+      # Pin an Xcode 16.x that R2025a's mex supports, rather than whatever
+      # (possibly newer) Xcode the image defaults to.
       - name: Select Xcode for MEX (macOS)
         if: runner.os == 'macOS'
         shell: bash
         run: |
           set -e
           XC=""
-          for v in 15.4 15.3 15.2 15.1 15.0.1 15.0; do
+          for v in 16.4 16.3 16.2 16.1 16.0; do
             if [ -d "/Applications/Xcode_${v}.app" ]; then XC="/Applications/Xcode_${v}.app"; break; fi
           done
           if [ -z "$XC" ]; then
-            XC=$(ls -d /Applications/Xcode_15*.app 2>/dev/null | sort -V | tail -1 || true)
+            XC=$(ls -d /Applications/Xcode_16*.app 2>/dev/null | sort -V | tail -1 || true)
           fi
           if [ -z "$XC" ]; then
-            echo "No Xcode 15.x found on runner; available Xcodes:"; ls -d /Applications/Xcode_*.app || true; exit 1
+            echo "No Xcode 16.x found on runner; available Xcodes:"; ls -d /Applications/Xcode_*.app || true; exit 1
           fi
           echo "Selecting $XC"
           sudo xcode-select -s "$XC/Contents/Developer"
diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index eebeac5..09fc7cb 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -122,32 +122,39 @@ jobs:
       fail-fast: false
       matrix:
         # Matlab actions support limited OS versions, check availability.
-        # macOS is pinned to macos-14 (arm64) because the macos-latest image
-        # ships an Xcode too new for R2024b's mex linker.
-        os: [ubuntu-latest, windows-latest, macos-14]
+        # macOS uses macos-15 (arm64), whose images ship only Xcode 16 and
+        # newer. R2024b's mex linker needs Xcode 15, so macOS builds with
+        # R2025a, which supports Xcode 16. Linux and Windows stay on R2024b.
+        include:
+          - os: ubuntu-latest
+            matlab: R2024b
+          - os: windows-latest
+            matlab: R2024b
+          - os: macos-15
+            matlab: R2025a
     steps:
       - uses: actions/checkout@v4
 
       - uses: matlab-actions/setup-matlab@v2
         with:
-          release: 'R2024b'
+          release: ${{ matrix.matlab }}
 
-      # MATLAB R2024b's mex linker is incompatible with the very new Xcode on
-      # the default image, so select a supported Xcode 15.x.
+      # Pin an Xcode 16.x that R2025a's mex supports, rather than whatever
+      # (possibly newer) Xcode the image defaults to.
       - name: Select Xcode for MEX (macOS)
         if: runner.os == 'macOS'
         shell: bash
         run: |
           set -e
           XC=""
-          for v in 15.4 15.3 15.2 15.1 15.0.1 15.0; do
+          for v in 16.4 16.3 16.2 16.1 16.0; do
             if [ -d "/Applications/Xcode_${v}.app" ]; then XC="/Applications/Xcode_${v}.app"; break; fi
           done
           if [ -z "$XC" ]; then
-            XC=$(ls -d /Applications/Xcode_15*.app 2>/dev/null | sort -V | tail -1 || true)
+            XC=$(ls -d /Applications/Xcode_16*.app 2>/dev/null | sort -V | tail -1 || true)
           fi
           if [ -z "$XC" ]; then
-            echo "No Xcode 15.x found on runner; available Xcodes:"; ls -d /Applications/Xcode_*.app || true; exit 1
+            echo "No Xcode 16.x found on runner; available Xcodes:"; ls -d /Applications/Xcode_*.app || true; exit 1
           fi
           echo "Selecting $XC"
           sudo xcode-select -s "$XC/Contents/Developer"