diff --git a/.github/workflows/stack.yaml b/.github/workflows/stack.yaml
index e2f011c..7138b63 100644
--- a/.github/workflows/stack.yaml
+++ b/.github/workflows/stack.yaml
@@ -18,7 +18,7 @@ jobs:
       fail-fast: false
       matrix:
         os: [macOS-latest, ubuntu-latest]
-        python-version: ["3.9", "3.10"]
+        python-version: ["3.9", "3.10", "3.11", "3.12"]
 
     env:
       CI_OS: ${{ matrix.os }}
@@ -30,18 +30,8 @@ jobs:
     # Each of these checkouts can be done on a feature branch
     # https://github.com/actions/checkout#checkout-a-different-branch
 
-    - name: Checkout OpenFF Toolkit
-      uses: actions/checkout@v4
-      with:
-        repository: openforcefield/openff-toolkit
-        path: openff-toolkit
-
-    - name: Checkout OpenFF Evaluator
-      uses: actions/checkout@v4
-      with:
-        repository: openforcefield/openff-evaluator
-        path: openff-evaluator
-
+    # Only check out the repos whose tests directly run; development
+    # installs of other packages are brought in via pip via micromamba
     - name: Checkout OpenFF Interchange
       uses: actions/checkout@v4
       with:
@@ -56,14 +46,9 @@ jobs:
 
     - name: Install most recent development versions
       run: |
-        micromamba remove --force openff-interchange -y
         micromamba remove --force openff-evaluator -y
-        micromamba remove --force openff-toolkit -y
 
         python -m pip install -e \
-          openff-toolkit/ \
-          openff-toolkit/utilities/test_plugins/ \
-          openff-evaluator/ \
           openff-interchange/ \
           openff-interchange/plugins/
 
diff --git a/devtools/conda-envs/full.yaml b/devtools/conda-envs/full.yaml
index e015fd0..4bad379 100644
--- a/devtools/conda-envs/full.yaml
+++ b/devtools/conda-envs/full.yaml
@@ -4,9 +4,9 @@ channels:
 dependencies:
   - python
   - pip
-  - openff-toolkit =0.14.4
+  - openff-toolkit =0.14.5
   - openff-evaluator
-  - openff-interchange =0.3.13
+  - openff-interchange =0.3.18
   - pymbar
   - pytest
   - pytest-randomly
@@ -25,3 +25,8 @@ dependencies:
   # foyer  # needs a release >0.12.0
   - mdanalysis
   - intermol
+  - pip:
+    - git+https://github.com/openforcefield/openff-toolkit.git@main
+    - git+https://github.com/openforcefield/openff-utilities.git@main
+    - git+https://github.com/openforcefield/openff-units.git@main
+    - git+https://github.com/openforcefield/openff-models.git@main