diff --git a/.tool-versions b/.tool-versions
index 71379b2fa7..785ba751f8 100644
--- a/.tool-versions
+++ b/.tool-versions
@@ -1,3 +1,3 @@
-elixir 1.9
-erlang 21.0.4
+elixir 1.9.1-otp-22
+erlang 22.0
 nodejs 10.11.0
diff --git a/mix.exs b/mix.exs
index c6c74689f9..af903bbdb0 100644
--- a/mix.exs
+++ b/mix.exs
@@ -14,7 +14,7 @@ defmodule BlockScout.Mixfile do
         plt_add_apps: ~w(ex_unit mix)a,
         ignore_warnings: ".dialyzer-ignore"
       ],
-      elixir: "~> 1.9",
+      elixir: "~> 1.9.1",
       preferred_cli_env: [
         coveralls: :test,
         "coveralls.detail": :test,