diff --git a/rust/hg-core/Cargo.toml b/rust/hg-core/Cargo.toml
--- a/rust/hg-core/Cargo.toml
+++ b/rust/hg-core/Cargo.toml
@@ -12,6 +12,6 @@
 byteorder = "1.3.1"
 lazy_static = "1.3.0"
 memchr = "2.2.0"
-rand = "> 0.6.4"
-rand_pcg = "> 0.1.0"
-regex = "^1.1"
+rand = "0.6.5"
+rand_pcg = "0.1.1"
+regex = "1.1.0"