diff --git a/docs/notebooks/symbolic.ipynb b/docs/notebooks/symbolic.ipynb
index e9daa05b6..dbad257d6 100644
--- a/docs/notebooks/symbolic.ipynb
+++ b/docs/notebooks/symbolic.ipynb
@@ -1,5 +1,28 @@
 {
  "cells": [
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "<!-- RTB_HEADER -- generated from the notebook metadata (rtb_header) by sync_bootstrap.py, do not hand-edit -->\n",
+    "<table>\n",
+    "  <tr>\n",
+    "    <td><div align=\"left\"><font size=\"30\">Robotics Toolbox for Python</font></div></td>\n",
+    "    <td><img src=\"figs/RobToolBox_RoundLogoB.png\" width=\"300\"></td>\n",
+    "  </tr>\n",
+    "</table>\n",
+    "\n",
+    "<p></p>\n",
+    "<div align=\"center\" style=\"font-size: 1.5em;\">Symbolic computation</div>\n",
+    "<p></p>\n",
+    "\n",
+    "(c) Peter Corke 2026\n",
+    "\n",
+    "Forward kinematics and inverse dynamics of a Puma 560 robot with symbolic joint variables, and generating code from the results.  The dynamics section takes a few minutes to run in full.\n",
+    "\n",
+    "> **Modernised 2026-10-19** to address API drift: this notebook was written for an earlier release of the Toolbox, and has been updated so that it runs with the current one."
+   ]
+  },
   {
    "cell_type": "code",
    "execution_count": null,
@@ -51,7 +74,7 @@
     "    print(f'Running {where} using RTB v{version}')\n",
     "    return colab\n",
     "\n",
-    "COLAB = await ensure_installed()\n"
+    "COLAB = await ensure_installed(extras=['ik'])\n"
    ]
   },
   {
@@ -560,7 +583,7 @@
    "outputs": [],
    "source": [
     "g = sym.symbol('g')\n",
-    "puma.gravity = [0, 0, g]"
+    "puma.gravity = [0, 0, -g]"
    ]
   },
   {
@@ -596,7 +619,7 @@
    "source": [
     "Now we compute the inverse dynamics as a function of symbolic joint coordinates, velocities, accelerations and gravity as well as a lot of numerical kinematic and dynamic parameters.\n",
     "\n",
-    "Note that this next step might take 10 minutes or more to execute (but the result will be impressive and worth the wait!)"
+    "This takes a second or so.  The result is impressive: each torque is an expression with thousands of terms.  Note that `gravity` is the acceleration due to gravity, so for the usual orientation of the Puma it is `[0, 0, -g]`."
    ]
   },
   {
@@ -629,69 +652,17 @@
    ]
   },
   {
-   "cell_type": "code",
-   "execution_count": null,
-   "metadata": {},
-   "outputs": [],
-   "source": [
-    "%time z = simplify(tau[4])"
-   ]
-  },
-  {
-   "cell_type": "code",
-   "execution_count": null,
-   "metadata": {},
-   "outputs": [],
-   "source": [
-    "%time z = simplify(tau[3])"
-   ]
-  },
-  {
-   "cell_type": "code",
-   "execution_count": null,
-   "metadata": {},
-   "outputs": [],
-   "source": [
-    "%time z = simplify(tau[2])"
-   ]
-  },
-  {
-   "cell_type": "code",
-   "execution_count": null,
-   "metadata": {},
-   "outputs": [],
-   "source": [
-    "%time z = simplify(tau[1])"
-   ]
-  },
-  {
-   "cell_type": "code",
-   "execution_count": null,
+   "cell_type": "markdown",
    "metadata": {},
-   "outputs": [],
    "source": [
-    "%time z = simplify(tau[0])"
+    "SymPy's `simplify` can reduce these expressions a lot, but it takes longer the more terms there are.  It took about a second for the last joint, 15 seconds for $\\tau_3$, 50 seconds for $\\tau_4$ and several minutes for $\\tau_2$, which we will not wait for."
    ]
   },
-  {
-   "cell_type": "code",
-   "execution_count": null,
-   "metadata": {},
-   "outputs": [],
-   "source": []
-  },
-  {
-   "cell_type": "code",
-   "execution_count": null,
-   "metadata": {},
-   "outputs": [],
-   "source": []
-  },
   {
    "cell_type": "markdown",
    "metadata": {},
    "source": [
-    "The result `tau` is not a NumPy array as it would be for the numeric case"
+    "The result `tau` is a NumPy array, as it is for the numeric case, but with `dtype=object` since each element is a SymPy expression"
    ]
   },
   {
@@ -707,7 +678,7 @@
    "cell_type": "markdown",
    "metadata": {},
    "source": [
-    "but it is the symbolic (SymPy) equivalent and it has the expected shape"
+    "and it has the expected shape"
    ]
   },
   {
@@ -781,7 +752,7 @@
    "metadata": {},
    "outputs": [],
    "source": [
-    "m = tau[0].coeff(qdd[0]).args\n",
+    "m = tau_0.coeff(qdd[0]).args\n",
     "m"
    ]
   },
@@ -800,7 +771,7 @@
    "metadata": {},
    "outputs": [],
    "source": [
-    "m = tau[0].coeff(qdd[1]).args\n",
+    "m = tau_0.coeff(qdd[1]).args\n",
     "m"
    ]
   },
@@ -819,7 +790,7 @@
    "metadata": {},
    "outputs": [],
    "source": [
-    "c = tau[0].coeff(qd[0]).args\n",
+    "c = tau_0.coeff(qd[0]).args\n",
     "c"
    ]
   },
@@ -837,7 +808,8 @@
    "metadata": {},
    "outputs": [],
    "source": [
-    "C = tau[0].coeff(qd[0]).coeff(qd[0]).args"
+    "C = tau_0.coeff(qd[0], 2).args\n",
+    "C"
    ]
   },
   {
@@ -850,11 +822,14 @@
    ]
   },
   {
-   "cell_type": "markdown",
+   "cell_type": "code",
    "metadata": {},
    "source": [
-    "c = tau[0].coeff(qd[0]).coeff(qd[1]).args"
-   ]
+    "c = tau_0.coeff(qd[0]).coeff(qd[1]).args\n",
+    "c"
+   ],
+   "execution_count": null,
+   "outputs": []
   },
   {
    "cell_type": "markdown",
@@ -944,7 +919,7 @@
    "metadata": {},
    "outputs": [],
    "source": [
-    "signif_terms = [t for t in tau_0.args if abs(t.args[0]) > 1e-6]\n",
+    "signif_terms = [t for t in tau_0.args if abs(t.args[0]) > 1e-2]\n",
     "signif_terms"
    ]
   },
@@ -1024,11 +999,9 @@
    "outputs": [],
    "source": [
     "subsdict = {}\n",
-    "sqdict = {}\n",
     "for j in range(puma.n):\n",
     "    subsdict[qd[j]] = 0\n",
-    "    subsdict[qdd[j]] = 0}\n",
-    "    sqdict[]"
+    "    subsdict[qdd[j]] = 0"
    ]
   },
   {
@@ -1037,7 +1010,7 @@
    "metadata": {},
    "outputs": [],
    "source": [
-    "tau_g = tau.subs(subsdict)\n",
+    "tau_g = [t.subs(subsdict) for t in tau]\n",
     "tau_g"
    ]
   },
@@ -1086,13 +1059,6 @@
    "source": [
     "t1.expand().subs(sqdict)"
    ]
-  },
-  {
-   "cell_type": "code",
-   "execution_count": null,
-   "metadata": {},
-   "outputs": [],
-   "source": []
   }
  ],
  "metadata": {
@@ -1154,6 +1120,18 @@
     "_Feature"
    ],
    "window_display": false
+  },
+  "rtb_header": {
+   "title": "Symbolic computation",
+   "paragraphs": [
+    "Forward kinematics and inverse dynamics of a Puma 560 robot with symbolic joint variables, and generating code from the results.  The dynamics section takes a few minutes to run in full."
+   ],
+   "modernised": "2026-10-19"
+  },
+  "rtb_bootstrap": {
+   "extras": [
+    "ik"
+   ]
   }
  },
  "nbformat": 4,