diff --git a/Cargo.toml b/Cargo.toml
index 65c8fc8..53040ea 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -39,7 +39,7 @@ version = "^1.0"
 optional = true
 
 [dependencies.sha2]
-version = "0.7"
+version = "0.6"
 optional = true
 
 [dependencies.failure]
@@ -48,7 +48,7 @@ default-features = false
 
 [dev-dependencies]
 hex = "0.3"
-sha2 = "0.7"
+sha2 = "0.6"
 bincode = "^0.9"
 
 [features]