diff --git a/README.md b/README.md
index af0a03a..a976a29 100644
--- a/README.md
+++ b/README.md
@@ -286,5 +286,5 @@ This library is licensed under the MIT-0 License. See the LICENSE file.
 
 # 9. Acknowledgements
 
-[@yapweiyih](https://github.com/yapweiyih) (EFS), [@josiahdavis](https://github.com/josiahdavis) and [@kianho](https://github.com/kianho) (vim), [@theoldfather](https://github.com/theoldfather) (docker relocation), [@aws/amazon-sagemaker-examples](https://github.com/aws/amazon-sagemaker-examples) (SageMaker local mode), [@yinsong1986](https://github.com/yinsong1986) (persistent custom conda environment), [@verdimrc](https://github.com/verdimrc) (misc.), the originator of git lol & lola (earlier traceable could be this
+[@yapweiyih](https://github.com/yapweiyih) (EFS, Streamlit), [@josiahdavis](https://github.com/josiahdavis) and [@kianho](https://github.com/kianho) (vim), [@theoldfather](https://github.com/theoldfather) (docker relocation), [@aws/amazon-sagemaker-examples](https://github.com/aws/amazon-sagemaker-examples) (SageMaker local mode), [@yinsong1986](https://github.com/yinsong1986) (persistent custom conda environment), [@verdimrc](https://github.com/verdimrc) (misc.), the originator of git lol & lola (earlier traceable could be this
 [blog](http://blog.kfish.org/2010/04/git-lola.html).
diff --git a/initsmnb/TEMPLATE-setup-my-sagemaker.sh b/initsmnb/TEMPLATE-setup-my-sagemaker.sh
index 97926e9..98055db 100755
--- a/initsmnb/TEMPLATE-setup-my-sagemaker.sh
+++ b/initsmnb/TEMPLATE-setup-my-sagemaker.sh
@@ -18,6 +18,7 @@ get_bin_dir() {
 
 BIN_DIR=$(get_bin_dir)
 ENABLE_EXPERIMENTAL=0
+ADVENTUROUS=0
 
 # Ensure that we run only on a SageMaker classic notebook instance.
 ${BIN_DIR}/ensure-smnb.sh
@@ -32,7 +33,6 @@ mkdir -p ~/.local/bin
 
 ${BIN_DIR}/install-cli.sh
 ${BIN_DIR}/adjust-sm-git.sh 'Firstname Lastname' first.last@email.abc
-${BIN_DIR}/change-jlab-ui.sh
 ${BIN_DIR}/fix-osx-keymap.sh
 ${BIN_DIR}/patch-bash-config.sh
 ${BIN_DIR}/fix-ipython.sh
@@ -43,6 +43,7 @@ ${BIN_DIR}/mount-efs-accesspoint.sh fsid,fsapid,mountpoint
 
 # These require jupyter lab restarted and browser reloaded, to see the changes.
 ${BIN_DIR}/patch-jupyter-config.sh
+${BIN_DIR}/change-jlab-ui.sh
 
 if [[ $ENABLE_EXPERIMENTAL == 1 ]]; then
     # NOTE: comment or uncomment tweaks in this stanza as necessary.
@@ -65,6 +66,8 @@ if [[ $ENABLE_EXPERIMENTAL == 1 ]]; then
     ${BIN_DIR}/change-docker-tmp-dir.sh
 
     ${BIN_DIR}/restart-docker.sh
+
+    [[ $ADVENTUROUS == 1 ]] && ${BIN_DIR}/upgrade-jupyter.sh
 fi
 
 # Final checks and next steps to see the changes in-effect
diff --git a/initsmnb/install-initsmnb.sh b/initsmnb/install-initsmnb.sh
index f5f68f2..cdcfe54 100755
--- a/initsmnb/install-initsmnb.sh
+++ b/initsmnb/install-initsmnb.sh
@@ -76,6 +76,7 @@ declare -a SCRIPTS=(
     change-docker-data-root.sh
     change-docker-tmp-dir.sh
     restart-docker.sh
+    upgrade-jupyter.sh
 )
 
 declare -a NESTED_FILES=(
@@ -87,6 +88,9 @@ CURL_OPTS="--fail-early -fL"
 FROM_LOCAL=0
 GIT_USER=''
 GIT_EMAIL=''
+ENABLE_EXPERIMENTAL=0
+ADVENTUROUS=0
+
 declare -a EFS=()
 
 declare -a HELP=(
@@ -95,6 +99,8 @@ declare -a HELP=(
     "[--git-user 'First Last']"
     "[--git-email me@abc.def]"
     "[--efs 'fsid,fsap,mp' [--efs ...]]"
+    "[--enable-experimental]"
+    "[--adventurous]"
 )
 
 ################################################################################
@@ -131,6 +137,15 @@ parse_args() {
             [[ "$2" != "" ]] && EFS+=("$2")
             shift 2
             ;;
+        --enable-experimental)
+            ENABLE_EXPERIMENTAL=1
+            shift
+            ;;
+        --adventurous)
+            ENABLE_EXPERIMENTAL=1
+            ADVENTUROUS=1
+            shift
+            ;;
         *)
             error_and_exit "Unknown argument: $key"
             ;;
@@ -212,6 +227,8 @@ sed \
     -e "s/Firstname Lastname/$GIT_USER/" \
     -e "s/first.last@email.abc/$GIT_EMAIL/" \
     -e "s/fsid,fsapid,mountpoint/$(efs2str ' ')/" \
+    -e "s/^ENABLE_EXPERIMENTAL=0/ENABLE_EXPERIMENTAL=$ENABLE_EXPERIMENTAL/" \
+    -e "s/^ADVENTUROUS=0$/ADVENTUROUS=$ADVENTUROUS/" \
     TEMPLATE-setup-my-sagemaker.sh >> setup-my-sagemaker.sh
 chmod ugo+x setup-my-sagemaker.sh
 
diff --git a/initsmnb/upgrade-jupyter.sh b/initsmnb/upgrade-jupyter.sh
new file mode 100755
index 0000000..4bc9a03
--- /dev/null
+++ b/initsmnb/upgrade-jupyter.sh
@@ -0,0 +1,178 @@
+#!/bin/bash
+
+FLAVOR=$(grep PRETTY_NAME /etc/os-release | cut -d'"' -f 2)
+if [[ $FLAVOR != "Amazon Linux 2" ]]; then
+    echo ${BASH_SOURCE[0]} does not support alinux instance.
+    exit 1
+fi
+
+
+################################################################################
+# STEP-00: upgrade to JLab-3.x
+#
+# [IMPLEMENTATION NOTES] Upgrade in-place JupyterSystemEnv instead of a new
+# dedicated conda env for the new JLab, because the existing conda environment
+# has sagemaker nbi agents installed (and possibly other pypi stuffs needed to
+# make notebook instance works).
+################################################################################
+CONDA_ENV_DIR=~/anaconda3/envs/JupyterSystemEnv/
+BIN_DIR=$CONDA_ENV_DIR/bin
+
+# Uninstall the old jupyter proxy, to unblock Streamlit.
+$BIN_DIR/jupyter serverextension disable --py nbserverproxy
+sed -i \
+    's/"nbserverproxy": true/"nbserverproxy": false/g' \
+    $CONDA_ENV_DIR/etc/jupyter/jupyter_notebook_config.json
+$BIN_DIR/pip uninstall --yes nbserverproxy
+
+# Completely remove these unused or outdated Python packages.
+$BIN_DIR/pip uninstall --yes nbdime jupyterlab-git
+
+# These will be outdated by Jlab-3.x which has built-in versions of them.
+declare -a EXTS_TO_DEL=(
+    jupyterlab-celltags
+    jupyterlab-toc
+    jupyterlab-git
+    nbdime-jupyterlab
+
+    sagemaker_examples  # Won't work on jlab-3.x anyway.
+)
+for i in "${EXTS_TO_DEL[@]}"; do
+    rm $CONDA_ENV_DIR/share/jupyter/lab/extensions/$i-*.tgz
+done
+
+# Upgrade jlab & extensions
+declare -a PKGS=(
+    notebook
+    jupyterlab
+    jupyter-server-proxy
+
+    jupyter
+    jupyter_client
+    jupyter_console
+    jupyter_core
+
+    jupyter_bokeh
+    nbdime
+
+    # jupyterlab_code_formatter requires formatters in its venv.
+    # See: https://github.com/ryantam626/jupyterlab_code_formatter/issues/153
+    jupyterlab_code_formatter
+    black
+    isort
+)
+$BIN_DIR/pip install --no-cache-dir --upgrade "${PKGS[@]}"
+
+
+################################################################################
+# STEP-01: Apply jlab-3+ configs
+################################################################################
+JUPYTER_CONFIG_ROOT=~/.jupyter/lab/user-settings/\@jupyterlab
+
+# Show traliling space is brand-new since JLab-3.2.0
+# See: https://jupyterlab.readthedocs.io/en/3.2.x/getting_started/changelog.html#id22
+mkdir -p $JUPYTER_CONFIG_ROOT/notebook-extension/
+cat << EOF > $JUPYTER_CONFIG_ROOT/notebook-extension/tracker.jupyterlab-settings
+{
+    // Notebook
+    // @jupyterlab/notebook-extension:tracker
+    // Notebook settings.
+    // **************************************
+    "codeCellConfig": {
+        "rulers": [80, 100],
+        "codeFolding": true,
+        "lineNumbers": true,
+        "lineWrap": "off",
+        "showTrailingSpace": true
+    },
+    "markdownCellConfig": {
+        "rulers": [80, 100],
+        "codeFolding": true,
+        "lineNumbers": true,
+        "lineWrap": "off",
+        "showTrailingSpace": true
+    },
+    "rawCellConfig": {
+        "rulers": [80, 100],
+        "lineNumbers": true,
+        "lineWrap": "off",
+        "showTrailingSpace": true
+    }
+}
+EOF
+
+mkdir -p $JUPYTER_CONFIG_ROOT/fileeditor-extension/
+cat << EOF > $JUPYTER_CONFIG_ROOT/fileeditor-extension/plugin.jupyterlab-settings
+{
+    // Text Editor
+    // @jupyterlab/fileeditor-extension:plugin
+    // Text editor settings.
+    // ***************************************
+    "editorConfig": {
+        "rulers": [80, 100],
+        "codeFolding": true,
+        "lineNumbers": true,
+        "lineWrap": "off",
+        "showTrailingSpace": true
+    }
+}
+EOF
+
+# macOptionIsMeta is brand-new since JLab-3.0.
+# See: https://jupyterlab.readthedocs.io/en/3.0.x/getting_started/changelog.html#other
+mkdir -p $JUPYTER_CONFIG_ROOT/terminal-extension/
+cat << EOF > $JUPYTER_CONFIG_ROOT/terminal-extension/plugin.jupyterlab-settings
+{
+    // Terminal
+    // @jupyterlab/terminal-extension:plugin
+    // Terminal settings.
+    // *************************************
+
+    // Font size
+    // The font size used to render text.
+    "fontSize": 11,
+
+    // Theme
+    // The theme for the terminal.
+    "theme": "dark",
+
+    // Treat option as meta key on macOS (new in JLab-3.0)
+    // Option key on macOS can be used as meta key. This enables to use shortcuts such as option + f
+    // to move cursor forward one word
+    "macOptionIsMeta": true
+}
+EOF
+
+# Undo the old "mac-option-is-meta" mechanism designed for jlab<3.0.
+echo "# JLab-3 + macOptionIsMeta deprecates fix-osx-keymap.sh" > ~/.inputrc
+rm ~/.ipython/profile_default/startup/01-osx-jupyterlab-keys.py
+
+# Show command palette on lhs navbar, similar behavior to smnb.
+mkdir -p $JUPYTER_CONFIG_ROOT/apputils-extension/
+cat << EOF > $JUPYTER_CONFIG_ROOT/apputils-extension/palette.jupyterlab-settings
+{
+    // Command Palette
+    // @jupyterlab/apputils-extension:palette
+    // Command palette settings.
+    // **************************************
+
+    // Modal Command Palette
+    // Whether the command palette should be modal or in the left panel.
+    "modal": false
+}
+EOF
+
+# Auto-apply black & isort when saving on notebook editor (but sadly, not on text editor).
+mkdir -p $JUPYTER_CONFIG_ROOT/jupyterlab_code_formatter-extension/
+cat << EOF > $JUPYTER_CONFIG_ROOT/jupyterlab_code_formatter-extension/settings.jupyterlab-settings
+{
+    // Jupyterlab Code Formatter
+    // @ryantam626/jupyterlab_code_formatter:settings
+    // Jupyterlab Code Formatter settings.
+    // **********************************************
+
+    // Auto format config
+    // Auto format code when save the notebook.
+    "formatOnSave": true,
+}
+EOF