diff --git a/Dockerfile b/Dockerfile
index 813acf122cb4f6f030671097267829e40e1e5c4e..26b43e25419eee2791f08e7123c4c67fdc0d717f 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -8,3 +8,18 @@ ADD environment.yml /tmp/environment.yml
 # All packages specified in environment.yml are installed in the base environment
 RUN conda env update -f /tmp/environment.yml && \
     conda clean -a -f -y
+
+# Basic Backend extensions
+RUN jupyter labextension uninstall jupyter-matplotlib
+
+RUN jupyter labextension install @jupyter-widgets/jupyterlab-manager@3.0.0
+
+RUN jupyter labextension install jupyter-matplotlib@0.9.0
+
+RUN jupyter labextension install jupyterlab-datawidgets@7.0.0
+
+RUN jupyter labextension install ipytree@0.2.1
+
+RUN jupyter labextension install k3d@2.9.3
+
+RUN jupyter labextension install ipyregulartable@0.2.0
diff --git a/bmcs_course/1_1_elastic_stiffness_of_the_composite.ipynb b/bmcs_course/1_1_elastic_stiffness_of_the_composite.ipynb
index c7f2dffc50c34c57b02c11dcf8043a61c5f2159a..ba65a6e2b1b17f4ad3449c2799c042d9dce4cb31 100644
--- a/bmcs_course/1_1_elastic_stiffness_of_the_composite.ipynb
+++ b/bmcs_course/1_1_elastic_stiffness_of_the_composite.ipynb
@@ -13,7 +13,7 @@
     "\n",
     "## Task\n",
     "What is the initial stiffness of a reinforced concrete cross section shown in the Figure with the thickness of 10~mm and width of 100 mm.\n",
-    "The cross-section is reinforced with 6 layers of textile fabrics made of CAR-EP3300 specified in the table below ![image.png](attachment:image.png)"
+    "The cross-section is reinforced with 6 layers of textile fabrics made of CAR-EP3300 specified in the table below ![image.png](../fig/mixture_rule_elastic.png)"
    ]
   },
   {
@@ -168,7 +168,7 @@
    "name": "python",
    "nbconvert_exporter": "python",
    "pygments_lexer": "ipython3",
-   "version": "3.8.3"
+   "version": "3.9.2"
   },
   "toc": {
    "base_numbering": 1,
diff --git a/bmcs_course/4_2_BS_EP_SH_I_A.ipynb b/bmcs_course/4_2_BS_EP_SH_I_A.ipynb
index a37b424762a43e9b9f8c41408a7de6cd8afe064c..726710c52a8e5623bac409fc41752963a548d0e7 100644
--- a/bmcs_course/4_2_BS_EP_SH_I_A.ipynb
+++ b/bmcs_course/4_2_BS_EP_SH_I_A.ipynb
@@ -1427,7 +1427,7 @@
    "name": "python",
    "nbconvert_exporter": "python",
    "pygments_lexer": "ipython3",
-   "version": "3.8.3"
+   "version": "3.9.2"
   },
   "toc": {
    "base_numbering": 1,
diff --git a/bmcs_course/5_1_Introspect_Damage_Evolution_Damage_initiation.ipynb b/bmcs_course/5_1_Introspect_Damage_Evolution_Damage_initiation.ipynb
index d75ec87a1ec245bd0cd5a647d5fc73bac0cb2e80..d66efcfb822506b30477a53df05b737480551aba 100644
--- a/bmcs_course/5_1_Introspect_Damage_Evolution_Damage_initiation.ipynb
+++ b/bmcs_course/5_1_Introspect_Damage_Evolution_Damage_initiation.ipynb
@@ -1073,7 +1073,7 @@
    "name": "python",
    "nbconvert_exporter": "python",
    "pygments_lexer": "ipython3",
-   "version": "3.8.3"
+   "version": "3.9.2"
   },
   "toc": {
    "base_numbering": 1,
diff --git a/environment.yml b/environment.yml
index e1a8b973d7a574fad3b774ba1ced11325bd3891f..4b9d9611d1808de332a9b307841b76d153dbd018 100644
--- a/environment.yml
+++ b/environment.yml
@@ -2,24 +2,24 @@ name: base
 channels:
 - conda-forge
 dependencies:
-- appmode
-- jupyter_contrib_nbextensions
-- traits
-- matplotlib
-- numpy
-- sympy
-- scipy
-- k3d
-- ipywidgets
-- mayavi
-- ipympl
+- appmode==0.8.0
+- jupyter_contrib_nbextensions==0.5.1
+- traits==6.1.1
+- matplotlib==3.3.3
+- numpy==1.19.4
+- sympy==1.7.1
+- scipy==1.5.3
+- k3d==2.9.3
+- ipywidgets==7.6.3
+- mayavi==4.7.2
+- ipympl==0.7.0
 - ipyregulartable
-- ipytree
-- traitsui
+- ipytree==0.2.1
+- traitsui==7.1.0
 - pip
 - pip:
-  - bmcs_utils
-  - bmcs_ibvpy
-  - bmcs_cross_section
-  - bmcs_beam
-  - bmcs_fragmentation
+  - bmcs-utils==0.0.20a0
+  - bmcs-ibvpy==0.0.4a0
+  - bmcs-cross_section==0.0.32a0
+  - bmcs-beam==0.0.10a0
+  - bmcs-fragmentation==0.0.2a0
diff --git a/tension/fragmentation.ipynb b/tension/fragmentation.ipynb
index bcb9c1c798f228342547f04bff3f569e2e21cd12..ea82ddbf7f481d7723343f31160c2fe1cd250782 100644
--- a/tension/fragmentation.ipynb
+++ b/tension/fragmentation.ipynb
@@ -2,8 +2,8 @@
  "cells": [
   {
    "cell_type": "code",
-   "execution_count": 4,
-   "id": "miniature-power",
+   "execution_count": 1,
+   "id": "industrial-defendant",
    "metadata": {},
    "outputs": [],
    "source": [
@@ -13,8 +13,8 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 5,
-   "id": "oriental-ordinance",
+   "execution_count": 2,
+   "id": "typical-peripheral",
    "metadata": {},
    "outputs": [],
    "source": [
@@ -23,14 +23,14 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 6,
-   "id": "complimentary-european",
+   "execution_count": 3,
+   "id": "existing-omega",
    "metadata": {},
    "outputs": [
     {
      "data": {
       "application/vnd.jupyter.widget-view+json": {
-       "model_id": "b43db16707024448bf2efb4919a94fc9",
+       "model_id": "54e9687bb36b4050abf6e800a1ee0339",
        "version_major": 2,
        "version_minor": 0
       },
@@ -46,10 +46,100 @@
     "pmcm.interact()"
    ]
   },
+  {
+   "cell_type": "code",
+   "execution_count": 4,
+   "id": "mighty-recipe",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "from ipytree import Tree"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 5,
+   "id": "eligible-bahamas",
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "application/vnd.jupyter.widget-view+json": {
+       "model_id": "9fc9de961ba64cffac50642d0a9da9d0",
+       "version_major": 2,
+       "version_minor": 0
+      },
+      "text/plain": [
+       "Tree()"
+      ]
+     },
+     "metadata": {},
+     "output_type": "display_data"
+    }
+   ],
+   "source": [
+    "Tree()"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 9,
+   "id": "amber-subdivision",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "import ipyregulartable as rt"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 10,
+   "id": "material-hotel",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "import numpy as np"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 12,
+   "id": "blocked-honduras",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "w = rt.RegularTableWidget(rt.NumpyDataModel(np.random.random((10,10))) )"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 13,
+   "id": "executive-throat",
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "application/vnd.jupyter.widget-view+json": {
+       "model_id": "7a85750248e8496d8eed5ebb4fd856b7",
+       "version_major": 2,
+       "version_minor": 0
+      },
+      "text/plain": [
+       "RegularTableWidget()"
+      ]
+     },
+     "metadata": {},
+     "output_type": "display_data"
+    }
+   ],
+   "source": [
+    "w"
+   ]
+  },
   {
    "cell_type": "code",
    "execution_count": null,
-   "id": "complicated-christmas",
+   "id": "rental-applicant",
    "metadata": {},
    "outputs": [],
    "source": []
@@ -57,9 +147,9 @@
  ],
  "metadata": {
   "kernelspec": {
-   "display_name": "bmcs_env",
+   "display_name": "base",
    "language": "python",
-   "name": "bmcs_env"
+   "name": "base"
   },
   "language_info": {
    "codemirror_mode": {
@@ -71,7 +161,7 @@
    "name": "python",
    "nbconvert_exporter": "python",
    "pygments_lexer": "ipython3",
-   "version": "3.9.2"
+   "version": "3.8.3"
   }
  },
  "nbformat": 4,