diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index ea83f39..f176556 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -14,8 +14,8 @@ jobs:
     strategy:
       matrix:
         python-version:
-        - "3.8" # oldest version; end of live in October 2024
-        - "3.11"
+        - "3.9" # oldest version; end of live in October 2025
+        - "3.12"
     steps:
     - uses: actions/checkout@v3
     - name: Set up Python ${{ matrix.python-version }}
diff --git a/critdd/tikz.py b/critdd/tikz.py
index a628bf3..90fb8f1 100644
--- a/critdd/tikz.py
+++ b/critdd/tikz.py
@@ -185,7 +185,7 @@ def _treatment(label, rank, xpos, ypos, anchor, reverse_x):
     return f"\\draw[treatment line] ([yshift=-2pt] axis cs:{rank}, 0) |- (axis cs:{xpos}, {-ypos})\n  node[treatment label, anchor={anchor}] {{{_label(label)}}};"
 def _label(label):
     parts = []
-    for i, part in enumerate(re.split("\$", label)): # split on equation boundaries
+    for i, part in enumerate(re.split("\\$", label)): # split on equation boundaries
         if i % 2 == 0: # if the current part is outside of an equation
             parts.append(re.sub("(?<!\\\\)_", "\\\\_", part)) # { "_", "\_" } -> "\_"
         else:
diff --git a/pyproject.toml b/pyproject.toml
index db227d4..bf1731f 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -10,7 +10,7 @@ dependencies = [
     "scipy",
     "networkx",
 ]
-requires-python = ">= 3.8"
+requires-python = ">= 3.9"
 keywords = [
     "machine learning",
     "benchmark",
@@ -24,10 +24,10 @@ classifiers = [
     "Topic :: Text Processing :: Markup :: LaTeX",
     "License :: OSI Approved :: GNU General Public License v3 (GPLv3)",
     "Programming Language :: Python :: 3",
-    "Programming Language :: Python :: 3.8",
     "Programming Language :: Python :: 3.9",
     "Programming Language :: Python :: 3.10",
     "Programming Language :: Python :: 3.11",
+    "Programming Language :: Python :: 3.12",
 ]
 readme = "README.md"
 authors = [