diff --git a/Dockerfile b/Dockerfile
index 26b43e25419eee2791f08e7123c4c67fdc0d717f..389e9edab6b2eb894ee621ebb94f3e36f450d213 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,5 +1,6 @@
 # Specify parent image. Please select a fixed tag here.
-ARG BASE_IMAGE=registry.git.rwth-aachen.de/jupyter/profiles/rwth-courses:2020-ss.1
+# ARG BASE_IMAGE=registry.git.rwth-aachen.de/jupyter/profiles/rwth-courses:2020-ss.1
+ARG BASE_IMAGE=registry.git.rwth-aachen.de/jupyter/profiles/rwth-minimal-2021-ss:latest
 FROM ${BASE_IMAGE}
 
 # .. Or update conda base environment to match specifications in environment.yml
diff --git a/mkappa/mkappa.ipynb b/mkappa/mkappa.ipynb
index 22f4f4ffa8be9854b2db9d8daf8b21249720925c..770cf1f47a152b9b0d4a054d6fd1675a87e2a3db 100644
--- a/mkappa/mkappa.ipynb
+++ b/mkappa/mkappa.ipynb
@@ -3,7 +3,7 @@
   {
    "cell_type": "code",
    "execution_count": 1,
-   "id": "funky-illustration",
+   "id": "million-hotel",
    "metadata": {},
    "outputs": [],
    "source": [
@@ -13,7 +13,7 @@
   {
    "cell_type": "code",
    "execution_count": 2,
-   "id": "fresh-century",
+   "id": "purple-japan",
    "metadata": {},
    "outputs": [],
    "source": [
@@ -28,7 +28,7 @@
   {
    "cell_type": "code",
    "execution_count": 3,
-   "id": "bigger-extent",
+   "id": "secondary-kruger",
    "metadata": {},
    "outputs": [],
    "source": [
@@ -38,7 +38,7 @@
   {
    "cell_type": "code",
    "execution_count": 4,
-   "id": "cutting-finnish",
+   "id": "talented-catalog",
    "metadata": {},
    "outputs": [],
    "source": [
@@ -55,7 +55,7 @@
   {
    "cell_type": "code",
    "execution_count": 5,
-   "id": "champion-badge",
+   "id": "informational-patrick",
    "metadata": {},
    "outputs": [
     {
@@ -122,7 +122,7 @@
   {
    "cell_type": "code",
    "execution_count": null,
-   "id": "difficult-retail",
+   "id": "unauthorized-metallic",
    "metadata": {},
    "outputs": [],
    "source": []
diff --git a/tension/fragmentation.ipynb b/tension/fragmentation.ipynb
index ea82ddbf7f481d7723343f31160c2fe1cd250782..cc54195f932f6446d6e13cb6943d484fa44601ee 100644
--- a/tension/fragmentation.ipynb
+++ b/tension/fragmentation.ipynb
@@ -3,7 +3,7 @@
   {
    "cell_type": "code",
    "execution_count": 1,
-   "id": "industrial-defendant",
+   "id": "thick-postcard",
    "metadata": {},
    "outputs": [],
    "source": [
@@ -14,7 +14,7 @@
   {
    "cell_type": "code",
    "execution_count": 2,
-   "id": "typical-peripheral",
+   "id": "affected-mother",
    "metadata": {},
    "outputs": [],
    "source": [
@@ -24,13 +24,13 @@
   {
    "cell_type": "code",
    "execution_count": 3,
-   "id": "existing-omega",
+   "id": "colored-clause",
    "metadata": {},
    "outputs": [
     {
      "data": {
       "application/vnd.jupyter.widget-view+json": {
-       "model_id": "54e9687bb36b4050abf6e800a1ee0339",
+       "model_id": "24abea4c54174a62a893fbdd1127c3d9",
        "version_major": 2,
        "version_minor": 0
       },
@@ -49,7 +49,7 @@
   {
    "cell_type": "code",
    "execution_count": 4,
-   "id": "mighty-recipe",
+   "id": "european-colombia",
    "metadata": {},
    "outputs": [],
    "source": [
@@ -59,7 +59,7 @@
   {
    "cell_type": "code",
    "execution_count": 5,
-   "id": "eligible-bahamas",
+   "id": "scientific-silly",
    "metadata": {},
    "outputs": [
     {
@@ -84,7 +84,7 @@
   {
    "cell_type": "code",
    "execution_count": 9,
-   "id": "amber-subdivision",
+   "id": "lonely-dairy",
    "metadata": {},
    "outputs": [],
    "source": [
@@ -94,7 +94,7 @@
   {
    "cell_type": "code",
    "execution_count": 10,
-   "id": "material-hotel",
+   "id": "accessory-citizenship",
    "metadata": {},
    "outputs": [],
    "source": [
@@ -104,7 +104,7 @@
   {
    "cell_type": "code",
    "execution_count": 12,
-   "id": "blocked-honduras",
+   "id": "subsequent-watershed",
    "metadata": {},
    "outputs": [],
    "source": [
@@ -114,7 +114,7 @@
   {
    "cell_type": "code",
    "execution_count": 13,
-   "id": "executive-throat",
+   "id": "several-holiday",
    "metadata": {},
    "outputs": [
     {
@@ -139,7 +139,7 @@
   {
    "cell_type": "code",
    "execution_count": null,
-   "id": "rental-applicant",
+   "id": "neural-lesson",
    "metadata": {},
    "outputs": [],
    "source": []