diff --git a/test/ci/debian:testing/Dockerfile b/test/ci/debian:testing/Dockerfile
index 84098ed02..790cd967f 100644
--- a/test/ci/debian:testing/Dockerfile
+++ b/test/ci/debian:testing/Dockerfile
@@ -1,46 +1,45 @@
 FROM debian:testing
 MAINTAINER Nicolas Richart <nicolas.richart@epfl.ch>
 
 RUN id
 
 RUN id _apt
 
 # # https://forums.debian.net/viewtopic.php?t=130558
 RUN rm -rf /etc/apt/trusted.gpg*
-RUN apt-key net-update
-
+RUN apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 648ACFD622F3D138 0E98404D386FA1D9
 # library dependencies
 RUN apt-get -qq update && apt-get -qq -y install \
     g++ gfortran clang cmake \
     openmpi-bin libmumps-dev libscotch-dev \
     libboost-dev libopenblas-dev \
     python3 python3-dev python3-numpy python3-scipy python3-mpi4py \
     && rm -rf /var/lib/apt/lists/*
 
 # for documentation
 RUN apt-get -qq update && apt-get -qq -y install \
     python3-sphinx \
     python3-sphinxcontrib.bibtex \
     python3-sphinx-rtd-theme \
     python3-breathe \
     python3-git python3-jinja2 \
     doxygen graphviz \
     && rm -rf /var/lib/apt/lists/*
 
 # for ci
 RUN apt-get -qq update && apt-get -qq -y install \
     gmsh python3-pytest python3-click python3-termcolor \
     ccache clang-format python3-flake8 python3-pip clang-tidy \
     curl git xsltproc jq \
     gcovr llvm binutils \
     ninja-build \
     && rm -rf /var/lib/apt/lists/*
 
 RUN pip3 install warning_parser
 
 COPY .openmpi /root/.openmpi
 
 # for debug
 RUN apt-get -qq update && apt-get -qq -y install \
     gdb valgrind \
     && rm -rf /var/lib/apt/lists/*