diff --git a/docs/io/optional/how_to_custom_source.ipynb b/docs/io/optional/how_to_custom_source.ipynb
index 046faf00780..a468d4d9d0e 100644
--- a/docs/io/optional/how_to_custom_source.ipynb
+++ b/docs/io/optional/how_to_custom_source.ipynb
@@ -190,11 +190,11 @@
    "outputs": [],
    "source": [
     "%matplotlib inline\n",
-    "plt.plot(mdl.transport.transport_state.spectrum_virtual.wavelength,\n",
-    "         mdl.transport.transport_state.spectrum_virtual.luminosity_density_lambda,\n",
+    "plt.plot(mdl.spectrum_solver.spectrum_virtual_packets.wavelength,\n",
+    "         mdl.spectrum_solver.spectrum_virtual_packets.luminosity_density_lambda,\n",
     "         color='red', label='truncated blackbody (custom packet source)')\n",
-    "plt.plot(mdl_norm.transport.transport_state.spectrum_virtual.wavelength,\n",
-    "         mdl_norm.transport.transport_state.spectrum_virtual.luminosity_density_lambda,\n",
+    "plt.plot(mdl_norm.spectrum_solver.spectrum_virtual_packets.wavelength,\n",
+    "         mdl_norm.spectrum_solver.spectrum_virtual_packets.luminosity_density_lambda,\n",
     "         color='blue', label='normal blackbody (default packet source)')\n",
     "plt.xlabel('$\\lambda [\\AA]$')\n",
     "plt.ylabel('$L_\\lambda$ [erg/s/$\\AA$]')\n",
diff --git a/docs/physics/spectrum/basic.ipynb b/docs/physics/spectrum/basic.ipynb
index 8a1ba43bd93..fc6bac795c3 100644
--- a/docs/physics/spectrum/basic.ipynb
+++ b/docs/physics/spectrum/basic.ipynb
@@ -47,7 +47,7 @@
    "source": [
     "from tardis.io.configuration.config_reader import Configuration\n",
     "from tardis.simulation import Simulation\n",
-    "from tardis.spectrum import TARDISSpectrum\n",
+    "from tardis.spectrum.spectrum import TARDISSpectrum\n",
     "from tardis.io.atom_data.util import download_atom_data\n",
     "from astropy import units as u\n",
     "import numpy as np\n",
@@ -460,7 +460,7 @@
    "name": "python",
    "nbconvert_exporter": "python",
    "pygments_lexer": "ipython3",
-   "version": "3.11.5"
+   "version": "3.12.3"
   }
  },
  "nbformat": 4,
diff --git a/docs/physics/update_and_conv/update_and_conv.ipynb b/docs/physics/update_and_conv/update_and_conv.ipynb
index 2735da970fc..cbc5c0c9618 100644
--- a/docs/physics/update_and_conv/update_and_conv.ipynb
+++ b/docs/physics/update_and_conv/update_and_conv.ipynb
@@ -462,7 +462,7 @@
     "#nu_lower = tardis_config.supernova.luminosity_wavelength_end.to(u.Hz, u.spectral)\n",
     "#nu_upper = tardis_config.supernova.luminosity_wavelength_start.to(u.Hz, u.spectral)\n",
     "\n",
-    "L_output = transport.transport_state.calculate_emitted_luminosity(0,np.inf)\n",
+    "L_output = sim.spectrum_solver.calculate_emitted_luminosity(0,np.inf)\n",
     "L_output"
    ]
   },
@@ -517,7 +517,7 @@
    },
    "outputs": [],
    "source": [
-    "sim.advance_state()"
+    "sim.advance_state(emitted_luminosity=L_output)"
    ]
   },
   {
@@ -596,7 +596,7 @@
    "name": "python",
    "nbconvert_exporter": "python",
    "pygments_lexer": "ipython3",
-   "version": "3.11.5"
+   "version": "3.12.3"
   },
   "vscode": {
    "interpreter": {