diff --git a/Cargo.toml b/Cargo.toml
index 953ad88..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]
@@ -47,8 +47,8 @@ version = "^0.1.1"
 default-features = false
 
 [dev-dependencies]
-hex = "0.2"
-sha2 = "^0.6"
+hex = "0.3"
+sha2 = "0.6"
 bincode = "^0.9"
 
 [features]
diff --git a/README.md b/README.md
index 5ea1c7b..b580cf8 100644
--- a/README.md
+++ b/README.md
@@ -119,7 +119,7 @@ eventually support VXEdDSA in curve25519-dalek.
 To install, add the following to your project's `Cargo.toml`:
 
     [dependencies.ed25519-dalek]
-    version = "^0.5"
+    version = "^0.6"
 
 Then, in your library or executable source, add:
 
@@ -129,7 +129,7 @@ To cause your application to build `ed25519-dalek` with the nightly feature
 enabled by default, instead do:
 
     [dependencies.ed25519-dalek]
-    version = "^0.5"
+    version = "^0.6"
     features = ["nightly"]
 
 To cause your application to instead build with the nightly feature enabled
@@ -145,7 +145,7 @@ verification.
 To enable [serde](https://serde.rs) support, build `ed25519-dalek` with:
 
     [dependencies.ed25519-dalek]
-    version = "^0.5"
+    version = "^0.6"
     features = ["serde"]