diff --git a/environment.yml b/environment.yml
index 5465941..3e29af1 100644
--- a/environment.yml
+++ b/environment.yml
@@ -7,7 +7,7 @@ channels:
   - conda-forge
 
 dependencies:
-  - numpy >=1.15
+  - numpy >=1.15,<2.0
   - biotite >=0.32
   - prody >=2.1
   - pytest >=5.2