diff --git a/mix.exs b/mix.exs
index 43b9e58..1e47878 100644
--- a/mix.exs
+++ b/mix.exs
@@ -48,7 +48,7 @@ defmodule Protox.Mixfile do
       {:ex_doc, "~> 0.22", only: [:dev], runtime: false},
       {:jason, "~> 1.2", optional: true},
       {:poison, "~> 4.0 or ~> 5.0 or ~> 6.0", only: [:test, :dev], optional: true},
-      {:propcheck, github: "ahamez/propcheck", only: [:test, :dev]}
+      {:propcheck, github: "alfert/propcheck", ref: "c564e89d", only: [:test, :dev]}
     ]
     |> maybe_add_muzak_pro()
   end
diff --git a/mix.lock b/mix.lock
index 64a5055..5bf0efb 100644
--- a/mix.lock
+++ b/mix.lock
@@ -21,7 +21,7 @@
   "makeup_erlang": {:hex, :makeup_erlang, "1.0.0", "6f0eff9c9c489f26b69b61440bf1b238d95badae49adac77973cbacae87e3c2e", [:mix], [{:makeup, "~> 1.0", [hex: :makeup, repo: "hexpm", optional: false]}], "hexpm", "ea7a9307de9d1548d2a72d299058d1fd2339e3d398560a0e46c27dab4891e4d2"},
   "nimble_parsec": {:hex, :nimble_parsec, "1.4.0", "51f9b613ea62cfa97b25ccc2c1b4216e81df970acd8e16e8d1bdc58fef21370d", [:mix], [], "hexpm", "9c565862810fb383e9838c1dd2d7d2c437b3d13b267414ba6af33e50d2d1cf28"},
   "poison": {:hex, :poison, "6.0.0", "9bbe86722355e36ffb62c51a552719534257ba53f3271dacd20fbbd6621a583a", [:mix], [{:decimal, "~> 2.1", [hex: :decimal, repo: "hexpm", optional: true]}], "hexpm", "bb9064632b94775a3964642d6a78281c07b7be1319e0016e1643790704e739a2"},
-  "propcheck": {:git, "https://github.com/ahamez/propcheck.git", "6138cd5efdf4f4de7b6c4d2694a0cdb40668869d", []},
+  "propcheck": {:git, "https://github.com/alfert/propcheck.git", "c564e89d3873caf9c6bf64a2af4bb3890e24ecf1", [ref: "c564e89d"]},
   "proper": {:git, "https://github.com/proper-testing/proper.git", "a5ae5669f01143b0828fc21667d4f5e344aa760b", [ref: "a5ae5669f01143b0828fc21667d4f5e344aa760b"]},
   "statistex": {:hex, :statistex, "1.0.0", "f3dc93f3c0c6c92e5f291704cf62b99b553253d7969e9a5fa713e5481cd858a5", [:mix], [], "hexpm", "ff9d8bee7035028ab4742ff52fc80a2aa35cece833cf5319009b52f1b5a86c27"},
 }