diff --git a/src/recipe.yaml b/src/recipe.yaml
index 5daf7e2..3b6b710 100644
--- a/src/recipe.yaml
+++ b/src/recipe.yaml
@@ -64,7 +64,7 @@ requirements:
     - awscli
     - bash
       # Pin Biopython 1.81: https://github.com/nextstrain/augur/issues/1373
-    - biopython =1.81
+    - biopython
     - bzip2
     - csvtk
     - curl