diff --git a/conda/meta.yaml b/conda/meta.yaml
index 986b0ac6..f93949fe 100644
--- a/conda/meta.yaml
+++ b/conda/meta.yaml
@@ -24,7 +24,7 @@ requirements:
     - typing_extensions
     - nptyping >=2.0.1
     - nlopt
-    - multimethod >=1.7,<2.0
+    - multimethod ==1.9.1
     - casadi
 
 test:
diff --git a/environment.yml b/environment.yml
index 21763683..d2f16eb2 100644
--- a/environment.yml
+++ b/environment.yml
@@ -20,7 +20,7 @@ dependencies:
   - nlopt
   - path
   - casadi
-  - multimethod >=1.7,<2.0
+  - multimethod ==1.9.1
   - pip
   - pip:
     - --editable=.
diff --git a/setup.py b/setup.py
index 9163f69a..e1ee0ed2 100644
--- a/setup.py
+++ b/setup.py
@@ -28,7 +28,7 @@ if not is_rtd and not is_appveyor and not is_azure and not is_conda:
     reqs = [
         "cadquery-ocp>=7.7.0a0,<7.8",
         "ezdxf",
-        "multimethod>=1.7,<2.0",
+        "multimethod==1.9.1",
         "nlopt",
         "nptyping==2.0.1",
         "typish",