diff --git a/.github/workflows/full-stack.yaml b/.github/workflows/full-stack.yaml
index 9cefc8f..b9005ba 100644
--- a/.github/workflows/full-stack.yaml
+++ b/.github/workflows/full-stack.yaml
@@ -19,6 +19,7 @@ jobs:
         os:
           - "ubuntu-latest"
           - "macos-latest"
+          - "ubuntu-24.04-arm"
         python-version:
           - "3.12"
 
diff --git a/devtools/conda-envs/full-stack.yaml b/devtools/conda-envs/full-stack.yaml
index a4d8b87..5dd5b10 100644
--- a/devtools/conda-envs/full-stack.yaml
+++ b/devtools/conda-envs/full-stack.yaml
@@ -1,16 +1,17 @@
 name: full-stack-tests
 channels:
+  - mmh/label/amber26
   - openeye
   - conda-forge
 dependencies:
   - python
   - setuptools =81
   - pip
-  - numpy >=2.4
+  - numpy >=2
   - pydantic =2.11.10
   - pint >=0.25
   - openff-toolkit >=0.18
-  - ambertools =24.8  # just to help solver
+  - ambertools =26.0  # just to help solver
   - openff-fragmenter
   - openff-interchange >=0.5.2
   - mdtraj
@@ -47,6 +48,3 @@ dependencies:
   - gromacs >=2024
   # https://github.com/conda-forge/lammps-feedstock/issues/207
   - lammps >=2024.08.29
-  - openmpi =4
-
-  - icu=75 # just to help solver