diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index ebfb3d2077bca5974bb4c8e84431101734ec69e3..1ca34cab32ac4751c6c0d4e1bda4b70b87655b5f 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -69,10 +69,10 @@ stages:
   -   git checkout devel
   -   git pull
   -   git checkout $WOLF_CORE_BRANCH
+  -   git pull
   - else
-  -   git clone ssh://git@gitlab.iri.upc.edu:2202/mobile_robotics/wolf_projects/wolf_lib/wolf.git
+  -   git clone -b $WOLF_CORE_BRANCH ssh://git@gitlab.iri.upc.edu:2202/mobile_robotics/wolf_projects/wolf_lib/wolf.git
   -   cd wolf
-  -   git checkout $WOLF_CORE_BRANCH
   - fi
   - mkdir -pv build
   - cd build
@@ -92,9 +92,9 @@ stages:
 ############ LICENSE HEADERS ############
 license_headers:
   stage: license
-  image: labrobotica/wolf_deps:16.04
+  image: labrobotica/wolf_deps:20.04
   cache:
-    - key: wolf-xenial
+    - key: wolf-focal
       paths:
       - ci_deps/wolf/
   except:
@@ -105,22 +105,6 @@ license_headers:
   script:
     - *license_header_definition
 
-############ UBUNTU 16.04 TESTS ############
-build_and_test:xenial:
-  stage: build_and_test
-  image: labrobotica/wolf_deps:16.04
-  cache:
-    - key: wolf-xenial
-      paths:
-      - ci_deps/wolf/
-  except:
-    - master
-  before_script:
-    - *preliminaries_definition
-    - *install_wolf_definition
-  script:
-    - *build_and_test_definition
-
 ############ UBUNTU 18.04 TESTS ############
 build_and_test:bionic:
   stage: build_and_test
diff --git a/include/imu/sensor/sensor_imu2d.h b/include/imu/sensor/sensor_imu2d.h
index 700d612ba2752ca3d115bd355658b7e30940ef73..880c9be07043a5f30da2df995e9e5d42ef8d9092 100644
--- a/include/imu/sensor/sensor_imu2d.h
+++ b/include/imu/sensor/sensor_imu2d.h
@@ -100,6 +100,7 @@ class SensorImu2d : public SensorBase
         double getAbInitialStdev() const;
         double getWbRateStdev() const;
         double getAbRateStdev() const;
+        bool   isGravityOrthogonal() const;
 
         ~SensorImu2d() override;
 
@@ -135,6 +136,11 @@ inline double SensorImu2d::getAbRateStdev() const
     return ab_rate_stdev;
 }
 
+inline bool SensorImu2d::isGravityOrthogonal() const
+{
+    return true;
+}
+
 } // namespace wolf
 
 #endif // SENSOR_Imu2D_H