diff --git a/CHANGELOG.md b/CHANGELOG.md
index 41afb26..0c7cfce 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -19,6 +19,13 @@ instructions, because git commits are used to generate release notes:
 
 <!-- scriv-insert-here -->
 
+<a id='changelog-21.0.0'></a>
+## v21.0.0 (2025-10-21)
+
+- [Improvement] Migrate from pylint and black to ruff. (by @Danyal-Faheem)
+
+- 💥[Feature] Upgrade to ulmo. (by @eemaanamir)
+
 <a id='changelog-20.0.0'></a>
 ## v20.0.0 (2025-06-05)
 
diff --git a/changelog.d/20250723_121728_danyal.faheem_migrate_ruff.md b/changelog.d/20250723_121728_danyal.faheem_migrate_ruff.md
deleted file mode 100644
index c36cf6d..0000000
--- a/changelog.d/20250723_121728_danyal.faheem_migrate_ruff.md
+++ /dev/null
@@ -1 +0,0 @@
-- [Improvement] Migrate from pylint and black to ruff. (by @Danyal-Faheem)
\ No newline at end of file
diff --git a/pyproject.toml b/pyproject.toml
index 9b0df71..535fb6a 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -25,14 +25,14 @@ classifiers = [
     "Programming Language :: Python :: 3.12",
 ]
 dependencies = [
-  "tutor>=20.0.0,<21.0.0",
+  "tutor>=21.0.0,<22.0.0",
 ]
 # these fields will be set by hatch_build.py
 dynamic = ["version"]
 
 [project.optional-dependencies]
 dev = [
-  "tutor[dev]>=20.0.0,<21.0.0",
+  "tutor[dev]>=21.0.0,<22.0.0",
   "ruff",
 ]
 
diff --git a/tutorcairn/__about__.py b/tutorcairn/__about__.py
index 9c9eb91..9bfcca5 100644
--- a/tutorcairn/__about__.py
+++ b/tutorcairn/__about__.py
@@ -1 +1 @@
-__version__ = "20.0.0"
+__version__ = "21.0.0"
diff --git a/tutorcairn/templates/cairn/build/cairn-superset/Dockerfile b/tutorcairn/templates/cairn/build/cairn-superset/Dockerfile
index 0b7d62a..63aa443 100644
--- a/tutorcairn/templates/cairn/build/cairn-superset/Dockerfile
+++ b/tutorcairn/templates/cairn/build/cairn-superset/Dockerfile
@@ -22,6 +22,8 @@ RUN apt-get update -qq \
         libxtst6 \
         wget \
         pkg-config \
+        default-libmysqlclient-dev \
+        build-essential \
     # Install GeckoDriver WebDriver
     && wget -q https://github.com/mozilla/geckodriver/releases/download/${GECKODRIVER_VERSION}/geckodriver-${GECKODRIVER_VERSION}-linux64.tar.gz -O - | tar xfz - -C /usr/local/bin \
     # Install Firefox
@@ -29,6 +31,9 @@ RUN apt-get update -qq \
     && ln -s /opt/firefox/firefox /usr/local/bin/firefox \
     && apt-get autoremove -yqq --purge wget && rm -rf /var/[log,tmp]/* /tmp/* /var/lib/apt/lists/*
 
+# Upgrade pip to avoid hash verification issues
+RUN pip install --upgrade pip
+
 # https://pypi.org/project/clickhouse-driver/
 # https://pypi.org/project/mysqlclient/
 # https://pypi.org/project/clickhouse-connect/