diff --git a/Cargo.toml b/Cargo.toml
index b220bc04b..f28474c82 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -36,7 +36,7 @@ debug = true
 
 [dependencies]
 fixedbitset = { version = "0.4.0", default-features = false }
-indexmap = { version = "1.6.2" }
+indexmap = { version = "~1.7" }
 quickcheck = { optional = true, version = "0.8", default-features = false }
 serde = { version = "1.0", optional = true }
 serde_derive = { version = "1.0", optional = true }