diff --git a/content/WhatIsAnARG_workbook2.ipynb b/content/WhatIsAnARG_workbook2.ipynb
index 0ecf59b..7acf30d 100644
--- a/content/WhatIsAnARG_workbook2.ipynb
+++ b/content/WhatIsAnARG_workbook2.ipynb
@@ -676,15 +676,8 @@
    "source": [
     "import demesdraw\n",
     "\n",
-    "try:\n",
-    "    # This requires msprime >= 1.4, not yet on pyodide\n",
-    "    cmd, parameters = msprime.provenance.parse_provenance(arg.provenance(0), arg)\n",
-    "    assert cmd == \"sim_ancestry\"  # just check we have the right (zeroth) provenance entry\n",
-    "except ValueError:\n",
-    "    # Hack the workbook for older msprime versions\n",
-    "    import pickle\n",
-    "    with open(\"data/msprime_param_hack.pkl\", 'rb') as picklefile:\n",
-    "        parameters = pickle.load(picklefile)\n",
+    "cmd, parameters = msprime.provenance.parse_provenance(arg.provenance(0), arg)\n",
+    "assert cmd == \"sim_ancestry\"  # just check we have the right (zeroth) provenance entry\n",
     "\n",
     "msprime_demography_object = parameters[\"demography\"]\n",
     "demesdraw.tubes(msprime_demography_object.to_demes(), log_time=False);"
diff --git a/content/data/msprime_param_hack.pkl b/content/data/msprime_param_hack.pkl
deleted file mode 100644
index 9956c8f..0000000
Binary files a/content/data/msprime_param_hack.pkl and /dev/null differ