diff --git a/docker-compose/sdptr-sim/Dockerfile b/docker-compose/sdptr-sim/Dockerfile
index bebf7b8ebf200bead417c2688515bc08636d1816..4ced94162fec862268fb63f13c9fa11c19918a74 100644
--- a/docker-compose/sdptr-sim/Dockerfile
+++ b/docker-compose/sdptr-sim/Dockerfile
@@ -5,11 +5,11 @@ RUN apt-get update && \
     apt-get clean
 
 # Install OPC-UA lib
-RUN git clone --depth 1 https://github.com/open62541/open62541 && \
+RUN git clone --depth 1 --branch 1.2 https://github.com/open62541/open62541 && \
     cd /open62541 && \
     git submodule update --init --recursive && \
     mkdir build && cd build && \
-    cmake .. -DBUILD_SHARED_LIBS=ON -DCMAKE_BUILD_TYPE=RelWithDebInfo -DUA_NAMESPACE_ZERO=FULL -DUA_MULTITHREADING=100 && make -j 4 install
+    bash -c "cmake .. -DBUILD_SHARED_LIBS=ON -DCMAKE_BUILD_TYPE=RelWithDebInfo -DUA_NAMESPACE_ZERO=FULL -DUA_MULTITHREADING=100 && make -j `nproc` install"
 
 # Update shared library cache
 RUN ldconfig
@@ -20,7 +20,7 @@ RUN cd / && git clone --depth 1 --branch master https://git.astron.nl/lofar2.0/s
 RUN cd /sdptr && \
     autoreconf -v -f -i && \
     ./configure && \
-    make -j 4 install
+    bash -c "make -j `nproc` install"
 
 WORKDIR /sdptr/src
 CMD ["sdptr", "--configfile=uniboard.conf", "--nodaemon"]