diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index f18c4d0ae..dd7b1a4db 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -52,7 +52,7 @@ jobs:
       - run: mvn -P "${{ matrix.profile }}" --batch-mode
 
   macos:
-    runs-on: [macos-14]
+    runs-on: [macos-15]
     strategy:
       fail-fast: false
       matrix:
@@ -81,10 +81,8 @@ jobs:
       - name: Set SDK version
         run: |
           export MACOSX_DEPLOYMENT_TARGET=${{ matrix.macos-deployment-target }}
-          export SDKROOT=$XCODE_16_DEVELOPER_DIR/Platforms/MacOSX.platform/Developer/SDKs/${{ matrix.sdk-version }}
-          export CMAKE_OSX_SYSROOT=$SDKROOT
+          export CMAKE_OSX_SYSROOT=$XCODE_16_DEVELOPER_DIR/Platforms/MacOSX.platform/Developer/SDKs/${{ matrix.sdk-version }}
           echo "MACOSX_DEPLOYMENT_TARGET=$MACOSX_DEPLOYMENT_TARGET" >> $GITHUB_ENV
-          echo "SDKROOT=$SDKROOT" >> $GITHUB_ENV
           echo "CMAKE_OSX_SYSROOT=$CMAKE_OSX_SYSROOT" >> $GITHUB_ENV
 
       - run: mvn -P "${{ matrix.profile }}" --batch-mode
diff --git a/.github/workflows/cross-compile.yml b/.github/workflows/cross-compile.yml
index fc7c7d12d..d942cd041 100644
--- a/.github/workflows/cross-compile.yml
+++ b/.github/workflows/cross-compile.yml
@@ -135,7 +135,7 @@ jobs:
           while  git pull --rebase && ! git push; do sleep 5; done
 
   macos:
-    runs-on: macos-14
+    runs-on: macos-15
     needs: create-branch
     strategy:
       matrix:
@@ -170,10 +170,8 @@ jobs:
       - name: Set SDK version
         run: |
           export MACOSX_DEPLOYMENT_TARGET=${{ matrix.macos-deployment-target }}
-          export SDKROOT=$XCODE_16_DEVELOPER_DIR/Platforms/MacOSX.platform/Developer/SDKs/${{ matrix.sdk-version }}
-          export CMAKE_OSX_SYSROOT=$SDKROOT
+          export CMAKE_OSX_SYSROOT=$XCODE_16_DEVELOPER_DIR/Platforms/MacOSX.platform/Developer/SDKs/${{ matrix.sdk-version }}
           echo "MACOSX_DEPLOYMENT_TARGET=$MACOSX_DEPLOYMENT_TARGET" >> $GITHUB_ENV
-          echo "SDKROOT=$SDKROOT" >> $GITHUB_ENV
           echo "CMAKE_OSX_SYSROOT=$CMAKE_OSX_SYSROOT" >> $GITHUB_ENV
       - name: Build with Maven
         run: |
diff --git a/ant/build.xml b/ant/build.xml
index 9d3c69689..0afe4f6d4 100644
--- a/ant/build.xml
+++ b/ant/build.xml
@@ -159,8 +159,15 @@
             <equals arg1="${os.target.arch}" arg2="arm_32"/>
         </condition>
 
+        <!-- SDK from env CMAKE_OSX_SYSROOT, if set. Not SDKROOT: the xcrun shims (make, c++) read it too,
+             and newer Xcodes cannot resolve old SDKs -->
+        <property environment="env"/>
+        <condition property="xcode.sysroot.arg" value="-DCMAKE_OSX_SYSROOT=&quot;${env.CMAKE_OSX_SYSROOT}&quot;" else="">
+            <isset property="env.CMAKE_OSX_SYSROOT"/>
+        </condition>
+
         <!-- Set cmake property "CMAKE_OSX_ARCHITECTURES" -->
-        <property name="cmake.generator.arg" value="-DCMAKE_OSX_ARCHITECTURES=${xcode.arch}"/>
+        <property name="cmake.generator.arg" value="-DCMAKE_OSX_ARCHITECTURES=${xcode.arch} ${xcode.sysroot.arg}"/>
     </target>
 
     <target name="gcc-props" if="use.gcc">