diff --git a/contractabi.nimble b/contractabi.nimble
index 3fc6346..fe3cc9d 100644
--- a/contractabi.nimble
+++ b/contractabi.nimble
@@ -5,4 +5,5 @@ license = "MIT"
 
 requires "stint"
 requires "stew"
+requires "questionable >= 0.10.0 & < 0.11.0"
 requires "upraises >= 0.1.0 & < 0.2.0"