diff --git a/.readthedocs.yaml b/.readthedocs.yaml
index 1218d6f..909a5c8 100644
--- a/.readthedocs.yaml
+++ b/.readthedocs.yaml
@@ -1,28 +1,18 @@
-# .readthedocs.yaml
-# Read the Docs configuration file
-# See https://docs.readthedocs.io/en/stable/config-file/v2.html for details
-
-# Required
 version: 2
 
-# Set the version of Python and other tools you might need
 build:
-  os: ubuntu-20.04
+  os: ubuntu-24.04
   tools:
-    python: "mambaforge-4.10"
-    # You can also specify other tool versions:
-    # nodejs: "16"
-    # rust: "1.55"
-    # golang: "1.17"
+    python: "mambaforge-latest"
 
-# Build documentation in the docs/ directory with Sphinx
-sphinx:
-   configuration: docs/conf.py
+python:
+  install:
+    - method: pip
+      path: .
 
-# If using Sphinx, optionally build your docs in additional formats such as PDF
-# formats:
-#    - pdf
+sphinx:
+  configuration: docs/conf.py
+  fail_on_warning: true
 
-# Optionally declare the Python requirements required to build your docs
 conda:
    environment: devtools/conda-envs/docs-env.yaml
diff --git a/devtools/conda-envs/docs-env.yaml b/devtools/conda-envs/docs-env.yaml
index 01d2ab4..b59d305 100644
--- a/devtools/conda-envs/docs-env.yaml
+++ b/devtools/conda-envs/docs-env.yaml
@@ -3,7 +3,7 @@ channels:
   - conda-forge
 dependencies:
     # Base depends
-  - python =3.11
+  - python =3.12
   - pip
 
     ### Core dependencies.
@@ -15,7 +15,7 @@ dependencies:
   - pydantic <2.0
   - openff-utilities >=0.1.5
   - openff-units
-  - openff-toolkit-base >=0.10.2
+  - openff-toolkit-base =0.17
   - openff-nagl-models
 
     # ESP storage
diff --git a/devtools/conda-envs/test_env_rdkit.yaml b/devtools/conda-envs/test_env_rdkit.yaml
index 204ded8..b8c2205 100644
--- a/devtools/conda-envs/test_env_rdkit.yaml
+++ b/devtools/conda-envs/test_env_rdkit.yaml
@@ -26,6 +26,8 @@ dependencies:
 
     # ESP calculations
   - psi4 =1.10
+    # See Lori comments in Psi4 slack Aug 5 2026
+  - libxc ==7.0.0
 
     # XTB charges
   - xtb-python
diff --git a/devtools/conda-envs/test_env_rdkit_and_openeye.yaml b/devtools/conda-envs/test_env_rdkit_and_openeye.yaml
index e3c0e35..a47b275 100644
--- a/devtools/conda-envs/test_env_rdkit_and_openeye.yaml
+++ b/devtools/conda-envs/test_env_rdkit_and_openeye.yaml
@@ -28,6 +28,8 @@ dependencies:
 
     # ESP calculations
   - psi4 =1.10
+    # See Lori comments in Psi4 slack Aug 5 2026
+  - libxc ==7.0.0
 
     # XTB charges
   - xtb-python