diff --git a/chapter1/fundamentals_code.ipynb b/chapter1/fundamentals_code.ipynb
index 75bb9405..ce60821f 100644
--- a/chapter1/fundamentals_code.ipynb
+++ b/chapter1/fundamentals_code.ipynb
@@ -458,11 +458,11 @@
    "metadata": {},
    "outputs": [],
    "source": [
-    "error_max = numpy.max(numpy.abs(uD.x.array - uh.x.array))\n",
-    "vertex_max = domain.comm.allreduce(error_max, op=MPI.MAX)\n",
+    "local_L_infty = numpy.max(numpy.abs(uD.x.array - uh.x.array))\n",
+    "L_infty = domain.comm.allreduce(local_L_infty, op=MPI.MAX)\n",
     "if domain.comm.rank == 0:  # Only print the error on one process\n",
     "    print(f\"Error_L2 : {error_L2:.2e}\")\n",
-    "    print(f\"Error_max : {error_max:.2e}\")"
+    "    print(f\"Error_max : {L_infty:.2e}\")"
    ]
   },
   {
diff --git a/chapter1/fundamentals_code.py b/chapter1/fundamentals_code.py
index 4775bb47..8bf0dd88 100644
--- a/chapter1/fundamentals_code.py
+++ b/chapter1/fundamentals_code.py
@@ -300,11 +300,11 @@
 # As we already have interpolated the exact solution into the first order space when creating the boundary condition,
 # we can compare the maximum values at any degree of freedom of the approximation space.
 
-error_max = numpy.max(numpy.abs(uD.x.array - uh.x.array))
-vertex_max = domain.comm.allreduce(error_max, op=MPI.MAX)
+local_L_infty = numpy.max(numpy.abs(uD.x.array - uh.x.array))
+L_infty = domain.comm.allreduce(local_L_infty, op=MPI.MAX)
 if domain.comm.rank == 0:  # Only print the error on one process
     print(f"Error_L2 : {error_L2:.2e}")
-    print(f"Error_max : {vertex_max:.2e}")
+    print(f"Error_max : {L_infty:.2e}")
 
 # ## Plotting the mesh using pyvista
 # We will visualizing the mesh using [pyvista](https://docs.pyvista.org/), an interface to the VTK toolkit.
diff --git a/pyproject.toml b/pyproject.toml
index 386bf735..5f071703 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -4,7 +4,7 @@ build-backend = "setuptools.build_meta"
 
 [project]
 name = "DOLFINx_Tutorial"
-version = "0.11.0"
+version = "0.12.0.dev0"
 dependencies = [
     "jupyter-book<2.0",
     "meshio",
@@ -13,7 +13,7 @@ dependencies = [
     "pandas",
     "tqdm",
     "pyvista[all]>=0.45.0",
-    "fenics-dolfinx>=0.11.0,<0.12.0",
+    "fenics-dolfinx>=0.12.0.dev0,<0.13.0",
     "sphinx-codeautolink",
     "trame_jupyter_extension",
     "jupytext",