diff --git a/qt6-after/qt6-migrated-legatus/docker_build.sh b/qt6-after/qt6-migrated-legatus/docker_build.sh
index 0ee13fe65..c9fccf7d0 100755
--- a/qt6-after/qt6-migrated-legatus/docker_build.sh
+++ b/qt6-after/qt6-migrated-legatus/docker_build.sh
@@ -21,6 +21,10 @@ elif [ "$1" = "ON" ]; then
   BUILD_RTI=ON
 fi
 
+# BUILD_GRANTLEE must be ON: codegen (IDL/DTC/FTC/SQL) generation is required
+# for the migrated services. Only the ON variant is supported and validated.
+BUILD_GRANTLEE="${BUILD_GRANTLEE:-ON}"
+
 # Run CMake configuration and build inside Docker
 docker run --rm \
   -e MIGRATE_PIPELINE_ROOT \
@@ -31,6 +35,11 @@ docker run --rm \
   -v ${MIGRATE_PIPELINE_ROOT}/rti_license.dat:/workspace/rti_license.dat \
   -w /workspace/qt-migration-legatus/qt6-after/qt6-migrated-legatus \
   ubuntu:26.04 bash -c "
+    # Fail the container on any command error and on failing pipeline
+    # stages (the make call below pipes through tee, which would otherwise
+    # mask a non-zero make exit code).
+    set -eo pipefail
+
     apt-get update -qq && \
     apt-get install -y -qq \
       build-essential \
@@ -40,6 +49,7 @@ docker run --rm \
       libqt6gui6 \
       libqt6widgets6 \
       qt6-base-dev \
+      qt6-websockets-dev \
       qt6-tools-dev-tools \
       qt6-tools-dev \
       qt6-l10n-tools \
@@ -65,11 +75,12 @@ docker run --rm \
 
     cmake .. \
       -DBUILD_RTI=${BUILD_RTI} \
+      -DBUILD_GRANTLEE=${BUILD_GRANTLEE} \
       -DBUILD_ARCGIS=OFF \
       -DCMAKE_CXX_STANDARD=17 \
       -DCMAKE_BUILD_TYPE=Release
 
-    make -j8 ddscore ddsftccore ddsQoS ddsconnector ddsfts migration_tests NGLLogger SV nglapplication nglcompression nglcoreapplication ngldb nglguiapplication nglsettings nglsingleapplication nglsinglecoreapplication ngltools ngltranslator nglwidgets qtsingleapplication qtsinglecoreapplication wms_json_ds tcpserver 2>&1 | tee build.log
+    make -j8 ddscore ddsftccore ddsQoS ddsconnector ddsfts migration_tests NGLLogger nglapplication nglcompression nglcoreapplication ngldb nglguiapplication nglsettings nglsingleapplication nglsinglecoreapplication ngltools ngltranslator nglwidgets qtsingleapplication qtsinglecoreapplication wms_json_ds tcpserver svcFileManagement svcFilterManagement flmTests 2>&1 | tee build.log
 
     # Run the CTest unit tests as an explicit validation step.
     # We are already inside build4 (cd build4 above), so --test-dir is the