diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index ae14e26121..55a58da332 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -40,7 +40,7 @@ jobs:
 
     - name: Base flopy installation
       run: |
-        pip install .
+        pip install . --use-feature=in-tree-build
 
     - name: Print flopy version
       run: |
diff --git a/etc/environment.yml b/etc/environment.yml
index bd12226fcd..9e7b494c6b 100644
--- a/etc/environment.yml
+++ b/etc/environment.yml
@@ -24,5 +24,5 @@ dependencies:
   - descartes
   - pyproj
   - shapely
-  - geos>=3.9.2,<3.9.0  # required until 3.9.2 is available
+  - geos
   - geojson