diff --git a/Cargo.toml b/Cargo.toml
index 9a19bb6f3..a52f74686 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -23,7 +23,7 @@ snap = {version="0.2"}
 atomicwrites = {version="0.2.2", optional=true}
 tempfile = "3.0"
 log = "0.4"
-combine = "3"
+combine = ">=3.6.0,<4.0.0"
 tempdir = "0.3"
 serde = "1.0"
 serde_derive = "1.0"