diff --git a/demo/demo_kirchhoff-love-clamped.py b/demo/demo_kirchhoff-love-clamped.py
index c02b598..37f3a25 100644
--- a/demo/demo_kirchhoff-love-clamped.py
+++ b/demo/demo_kirchhoff-love-clamped.py
@@ -221,8 +221,6 @@ def all_boundary(x):
 
 w, M = u_h.split()
 
-if len(cells) > 0:
+if cells.array.shape[0] > 0:
     value = w.eval(point, cells.array[0])
     print(value[0])
-
-# TODO: IO?
diff --git a/demo/demo_reissner-mindlin-clamped-tdnns.py b/demo/demo_reissner-mindlin-clamped-tdnns.py
index d2eaa17..7e65a38 100644
--- a/demo/demo_reissner-mindlin-clamped-tdnns.py
+++ b/demo/demo_reissner-mindlin-clamped-tdnns.py
@@ -254,6 +254,6 @@ def all_boundary(x):
 
 theta, w, M = u_h.split()
 
-if len(cells) > 0:
+if cells.array.shape[0] > 0:
     value = w.eval(point, cells.array[0])
     print(value[0])
diff --git a/demo/demo_reissner-mindlin-clamped.py b/demo/demo_reissner-mindlin-clamped.py
index 370242b..17ff6aa 100644
--- a/demo/demo_reissner-mindlin-clamped.py
+++ b/demo/demo_reissner-mindlin-clamped.py
@@ -232,7 +232,7 @@ def all_boundary(x):
 
 theta, w, R_gamma, p = u_.split()
 
-if len(cells) > 0:
+if cells.array.shape[0] > 0:
     value = w.eval(point, cells.array[0])
     print(value[0])
     # NOTE: FEniCS-Shells (old dolfin) `demo/documented/reissner-mindlin-clamped`
diff --git a/demo/demo_reissner-mindlin-simply-supported.py b/demo/demo_reissner-mindlin-simply-supported.py
index ef5401e..95749b4 100644
--- a/demo/demo_reissner-mindlin-simply-supported.py
+++ b/demo/demo_reissner-mindlin-simply-supported.py
@@ -249,7 +249,7 @@ def make_bc(value, V, on_boundary):
 
 theta, w, R_gamma, p = u_.split()
 
-if len(cells) > 0:
+if cells.array.shape[0] > 0:
     value = w.eval(point, cells.array[0])
     print(value[0])
 # -
diff --git a/launch-container.sh b/launch-container.sh
index f1329de..87960d9 100755
--- a/launch-container.sh
+++ b/launch-container.sh
@@ -1,3 +1,3 @@
 #!/bin/bash
-CONTAINER_ENGINE="docker"
-${CONTAINER_ENGINE} run -ti -v $(pwd):/shared -w /shared dolfinx/dolfinx:v0.9.0
+CONTAINER_ENGINE="podman"
+${CONTAINER_ENGINE} run -ti -v $(pwd):/shared -w /shared dolfinx/dolfinx:nightly