diff --git a/.gitignore b/.gitignore
index 6185788..43cb8c9 100644
--- a/.gitignore
+++ b/.gitignore
@@ -3,5 +3,6 @@
 __pycache__/
 build/
 dist/
+docker/data/
 *.egg-info/
 node_modules/
diff --git a/README.md b/README.md
index 9973f20..2f2bb42 100644
--- a/README.md
+++ b/README.md
@@ -192,7 +192,7 @@ Oracle Java image yourself:
    ```
 
 2. Visit [the Java download page](https://www.java.com/en/download/manual.jsp) and get the *Linux x64* tar archive of
-   Oracle Java version `8u251`. Save it to the `docker` subdirectory of the previously cloned repository as
+   Oracle Java version `8u251`. Save it to the `docker/data` subdirectory of the previously cloned repository as
    `jre-8u251-linux-x64.tar.gz`. If you would like to also use Oracle Java 7, get `jre-7u80-linux-x64.tar.gz` from
    [Oracle's Java archive](https://www.oracle.com/java/technologies/javase/javase7-archive-downloads.html) (this
    requires an free Oracle account).
diff --git a/docker/Dockerfile_html5 b/docker/Dockerfile_html5
index 250f61b..3018012 100644
--- a/docker/Dockerfile_html5
+++ b/docker/Dockerfile_html5
@@ -1,6 +1,14 @@
 FROM node:14
 LABEL maintainer="Maximilian Heuwes <m.heuwes@fz-juelich.de>"
 
+# Set packages from deb.debian.com to archive.debian.com
+COPY ./config/buster-sources.list /etc/apt/sources.list
+RUN apt-get update && \
+    apt-get install -y wget && \
+    wget -O /tmp/debian-keyring.deb http://http.us.debian.org/debian/pool/main/d/debian-archive-keyring/debian-archive-keyring_2025.1_all.deb && \
+    dpkg -i /tmp/debian-keyring.deb && \
+    rm /tmp/debian-keyring.deb
+
 RUN apt-get update && \
     apt-get install -y --no-install-recommends ca-certificates curl net-tools procps python-numpy \
                                                python-pip python-pyquery python-setuptools python-wheel tar && \
diff --git a/docker/Dockerfile_openjdk-7 b/docker/Dockerfile_openjdk-7
index 94e20cd..acccd48 100644
--- a/docker/Dockerfile_openjdk-7
+++ b/docker/Dockerfile_openjdk-7
@@ -1,9 +1,16 @@
 FROM debian:jessie
 LABEL maintainer="Ingo Meyer <i.meyer@fz-juelich.de>"
 
-# Install needed packages and Java dependencies (second `apt-get install` call)
+# Set packages from deb.debian.com to archive.debian.com
+COPY ./config/jessie-sources.list /etc/apt/sources.list
 RUN apt-get update && \
-    apt-get install -y --no-install-recommends ca-certificates curl eterm fluxbox net-tools procps python-numpy \
+    apt-get install -y wget && \
+    wget -O /tmp/debian-keyring.deb http://http.us.debian.org/debian/pool/main/d/debian-archive-keyring/debian-archive-keyring_2025.1_all.deb && \
+    dpkg -i /tmp/debian-keyring.deb && \
+    rm /tmp/debian-keyring.deb
+
+# Install needed packages and Java dependencies (second `apt-get install` call)
+RUN apt-get install -y --no-install-recommends ca-certificates curl eterm fluxbox net-tools procps python-numpy \
                                                python-pip python-pyquery python-wheel supervisor tar x11vnc xvfb && \
     apt-get install -y --no-install-recommends ca-certificates-java initscripts java-common libasound2 \
                                                libatk-wrapper-java-jni libatk1.0-0 libc6 libcairo2 libcups2 \
@@ -60,7 +67,7 @@ COPY supervisord_openjdk-7.conf /etc/supervisor/conf.d/supervisord.conf
 
 WORKDIR /root/
 
-ENV DISPLAY :0
+ENV DISPLAY=:0
 EXPOSE 8080
 
 ENTRYPOINT ["/usr/local/bin/docker-entrypoint"]
diff --git a/docker/Dockerfile_openjdk-8 b/docker/Dockerfile_openjdk-8
index a64e88a..675a08f 100644
--- a/docker/Dockerfile_openjdk-8
+++ b/docker/Dockerfile_openjdk-8
@@ -1,9 +1,16 @@
 FROM debian:stretch
 LABEL maintainer="Ingo Meyer <i.meyer@fz-juelich.de>"
 
-# Install needed packages and Java dependencies (second `apt-get install` call)
+# Set packages from deb.debian.com to archive.debian.com
+COPY ./config/stretch-sources.list /etc/apt/sources.list
 RUN apt-get update && \
-    apt-get install -y --no-install-recommends ca-certificates curl eterm fluxbox net-tools procps python-numpy \
+    apt-get install -y wget && \
+    wget -O /tmp/debian-keyring.deb http://http.us.debian.org/debian/pool/main/d/debian-archive-keyring/debian-archive-keyring_2025.1_all.deb && \
+    dpkg -i /tmp/debian-keyring.deb && \
+    rm /tmp/debian-keyring.deb
+
+# Install needed packages and Java dependencies (second `apt-get install` call)
+RUN apt-get install -y --no-install-recommends ca-certificates curl eterm fluxbox net-tools procps python-numpy \
                                                python-pip python-pyquery python-setuptools python-wheel supervisor tar \
                                                x11vnc xvfb && \
     apt-get install -y --no-install-recommends adwaita-icon-theme ca-certificates ca-certificates-java \
@@ -76,7 +83,7 @@ COPY supervisord_openjdk-8.conf /etc/supervisor/conf.d/supervisord.conf
 
 WORKDIR /root/
 
-ENV DISPLAY :0
+ENV DISPLAY=:0
 EXPOSE 8080
 
 ENTRYPOINT ["/usr/local/bin/docker-entrypoint"]
diff --git a/docker/Dockerfile_oraclejre-7 b/docker/Dockerfile_oraclejre-7
index 77a602b..05f25ff 100644
--- a/docker/Dockerfile_oraclejre-7
+++ b/docker/Dockerfile_oraclejre-7
@@ -1,9 +1,16 @@
 FROM debian:stretch
 LABEL maintainer="Ingo Meyer <i.meyer@fz-juelich.de>"
 
-# Install needed packages and Java dependencies (second `apt-get install` call)
+# Set packages from deb.debian.com to archive.debian.com
+COPY ./config/stretch-sources.list /etc/apt/sources.list
 RUN apt-get update && \
-    apt-get install -y --no-install-recommends ca-certificates curl eterm fluxbox net-tools procps python-numpy \
+    apt-get install -y wget && \
+    wget -O /tmp/debian-keyring.deb http://http.us.debian.org/debian/pool/main/d/debian-archive-keyring/debian-archive-keyring_2025.1_all.deb && \
+    dpkg -i /tmp/debian-keyring.deb && \
+    rm /tmp/debian-keyring.deb
+
+# Install needed packages and Java dependencies (second `apt-get install` call)
+RUN apt-get install -y --no-install-recommends ca-certificates curl eterm fluxbox net-tools procps python-numpy \
                                                python-pip python-pyquery python-setuptools python-wheel supervisor tar \
                                                x11vnc xvfb && \
     apt-get install -y --no-install-recommends adwaita-icon-theme ca-certificates ca-certificates-java \
@@ -49,7 +56,7 @@ RUN NOVNC_VERSION="1.1.0" && \
     ln -s "/opt/noVNC-${NOVNC_VERSION}/utils/launch.sh" /usr/local/bin/launch_novnc && \
     rm -f /tmp/novnc.tar.gz
 
-COPY jre-7u80-linux-x64.tar.gz /opt/java_packages/7u80/jre-7u80-linux-x64.tar.gz
+COPY data/jre-7u80-linux-x64.tar.gz /opt/java_packages/7u80/jre-7u80-linux-x64.tar.gz
 
 COPY entrypoint.sh /usr/local/bin/docker-entrypoint
 COPY get_java_viewer.py /usr/local/bin/get_java_viewer
@@ -58,7 +65,7 @@ COPY supervisord_oraclejre-7.conf /etc/supervisor/conf.d/supervisord.conf
 
 WORKDIR /root/
 
-ENV DISPLAY :0
+ENV DISPLAY=:0
 EXPOSE 8080
 
 ENTRYPOINT ["/usr/local/bin/docker-entrypoint"]
diff --git a/docker/Dockerfile_oraclejre-8 b/docker/Dockerfile_oraclejre-8
index 71268aa..a95ff10 100644
--- a/docker/Dockerfile_oraclejre-8
+++ b/docker/Dockerfile_oraclejre-8
@@ -1,9 +1,16 @@
 FROM debian:stretch
 LABEL maintainer="Ingo Meyer <i.meyer@fz-juelich.de>"
 
-# Install needed packages and Java dependencies (second `apt-get install` call)
+# Set packages from deb.debian.com to archive.debian.com
+COPY ./config/stretch-sources.list /etc/apt/sources.list
 RUN apt-get update && \
-    apt-get install -y --no-install-recommends ca-certificates curl eterm fluxbox net-tools procps python-numpy \
+    apt-get install -y wget && \
+    wget -O /tmp/debian-keyring.deb http://http.us.debian.org/debian/pool/main/d/debian-archive-keyring/debian-archive-keyring_2025.1_all.deb && \
+    dpkg -i /tmp/debian-keyring.deb && \
+    rm /tmp/debian-keyring.deb
+
+# Install needed packages and Java dependencies (second `apt-get install` call)
+RUN apt-get install -y --no-install-recommends ca-certificates curl eterm fluxbox net-tools procps python-numpy \
                                                python-pip python-pyquery python-setuptools python-wheel supervisor tar \
                                                x11vnc xvfb && \
     apt-get install -y --no-install-recommends adwaita-icon-theme ca-certificates ca-certificates-java \
@@ -49,7 +56,7 @@ RUN NOVNC_VERSION="1.1.0" && \
     ln -s "/opt/noVNC-${NOVNC_VERSION}/utils/launch.sh" /usr/local/bin/launch_novnc && \
     rm -f /tmp/novnc.tar.gz
 
-COPY jre-8u251-linux-x64.tar.gz /opt/java_packages/8u251/jre-8u251-linux-x64.tar.gz
+COPY data/jre-8u251-linux-x64.tar.gz /opt/java_packages/8u251/jre-8u251-linux-x64.tar.gz
 
 COPY entrypoint.sh /usr/local/bin/docker-entrypoint
 COPY get_java_viewer.py /usr/local/bin/get_java_viewer
@@ -58,7 +65,7 @@ COPY supervisord_oraclejre-8.conf /etc/supervisor/conf.d/supervisord.conf
 
 WORKDIR /root/
 
-ENV DISPLAY :0
+ENV DISPLAY=:0
 EXPOSE 8080
 
 ENTRYPOINT ["/usr/local/bin/docker-entrypoint"]
diff --git a/docker/Makefile b/docker/Makefile
index 528082d..98db335 100644
--- a/docker/Makefile
+++ b/docker/Makefile
@@ -15,18 +15,19 @@ build-openjdk:
 	done
 
 build-oracle:
-	@if [[ -f "jre-7u80-linux-x64.tar.gz" ]]; then \
+	@if [ -f "data/jre-7u80-linux-x64.tar.gz" ]; then \
 	    docker build -t "sciapp/nojava-ipmi-kvm:latest-oraclejre-7" -f "Dockerfile_oraclejre-7" .; \
-	    if [[ "$$(git symbolic-ref -q HEAD)" == "refs/heads/master" ]]; then \
+	    if [ "$$(git symbolic-ref -q HEAD)" = "refs/heads/main" ]; then \
 	        docker tag "sciapp/nojava-ipmi-kvm:latest-oraclejre-7" \
 	                   "sciapp/nojava-ipmi-kvm:v$(PACKAGE_VERSION)-oraclejre-7"; \
 	    fi; \
 	else \
 	    >&2 echo "Please download \"jre-7u80-linux-x64.tar.gz\" to build an Oracle Java 7 docker image."; \
-	fi; \
-	if [[ -f "jre-8u251-linux-x64.tar.gz" ]]; then \
+	fi;
+
+	@if [ -f "data/jre-8u251-linux-x64.tar.gz" ]; then \
 	    docker build -t "sciapp/nojava-ipmi-kvm:latest-oraclejre-8" -f "Dockerfile_oraclejre-8" .; \
-	    if [[ "$$(git symbolic-ref -q HEAD)" == "refs/heads/master" ]]; then \
+	    if [ "$$(git symbolic-ref -q HEAD)" = "refs/heads/master" ]; then \
 	        docker tag "sciapp/nojava-ipmi-kvm:latest-oraclejre-8" \
 	                   "sciapp/nojava-ipmi-kvm:v$(PACKAGE_VERSION)-oraclejre-8"; \
 	    fi; \
diff --git a/docker/config/buster-sources.list b/docker/config/buster-sources.list
new file mode 100644
index 0000000..52fc13b
--- /dev/null
+++ b/docker/config/buster-sources.list
@@ -0,0 +1,2 @@
+deb [trusted=yes] http://archive.debian.org/debian buster main
+deb [trusted=yes] http://archive.debian.org/debian-security buster/updates main
diff --git a/docker/config/jessie-sources.list b/docker/config/jessie-sources.list
new file mode 100644
index 0000000..785de9b
--- /dev/null
+++ b/docker/config/jessie-sources.list
@@ -0,0 +1,2 @@
+deb [trusted=yes] http://archive.debian.org/debian jessie main
+deb [trusted=yes] http://archive.debian.org/debian-security jessie/updates main
diff --git a/docker/config/stretch-sources.list b/docker/config/stretch-sources.list
new file mode 100644
index 0000000..9ae3d3d
--- /dev/null
+++ b/docker/config/stretch-sources.list
@@ -0,0 +1,2 @@
+deb [trusted=yes] http://archive.debian.org/debian stretch main
+deb [trusted=yes] http://archive.debian.org/debian-security stretch/updates main
diff --git a/docker/data/.gitkeep b/docker/data/.gitkeep
new file mode 100644
index 0000000..8b13789
--- /dev/null
+++ b/docker/data/.gitkeep
@@ -0,0 +1 @@
+