diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index d66ff978b..4a9602f20 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -216,6 +216,7 @@ pkg:alpine:
   - docker login -u ${CI_REGISTRY_USER} -p ${CI_REGISTRY_PASSWORD} ${CI_REGISTRY}
   script:
   - docker buildx build ${DOCKER_OPTS}
+      --pull
       --output type=docker
       --target app
       --build-arg ARCH=${ARCH}
diff --git a/include/villas/dumper.hpp b/include/villas/dumper.hpp
index 4d8bfd225..560f4e509 100644
--- a/include/villas/dumper.hpp
+++ b/include/villas/dumper.hpp
@@ -43,7 +43,7 @@ public:
 	int openSocket();
 	int closeSocket();
 
-	void writeData(uint len, double *yData, double *xData = nullptr);
+	void writeData(unsigned len, double *yData, double *xData = nullptr);
 };
 
 } /* namespace node */
diff --git a/packaging/docker/Dockerfile.alpine b/packaging/docker/Dockerfile.alpine
index 8688d829d..f17b2a5af 100644
--- a/packaging/docker/Dockerfile.alpine
+++ b/packaging/docker/Dockerfile.alpine
@@ -28,7 +28,7 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 ###################################################################################
 
-FROM alpine:edge AS dev
+FROM alpine:3.13.1 AS dev
 
 ARG DISTRO=alpine
 ARG ARCH=x86_64