diff --git a/mix.exs b/mix.exs
index f8fcfd9..5450e88 100644
--- a/mix.exs
+++ b/mix.exs
@@ -29,7 +29,7 @@ defmodule ElixirFundamentals.Mixfile do
   # Type "mix help deps" for more examples and options
   defp deps do
     [
-      {:poison, "4.0.1"},
+      {:poison, "== 6.0.0"},
       {:httpoison, "== 1.8.2"}
     ]
   end
diff --git a/mix.lock b/mix.lock
index 7953716..93adce0 100644
--- a/mix.lock
+++ b/mix.lock
@@ -6,7 +6,7 @@
   "metrics": {:hex, :metrics, "1.0.1", "25f094dea2cda98213cecc3aeff09e940299d950904393b2a29d191c346a8486", [:rebar3], [], "hexpm", "69b09adddc4f74a40716ae54d140f93beb0fb8978d8636eaded0c31b6f099f16"},
   "mimerl": {:hex, :mimerl, "1.2.0", "67e2d3f571088d5cfd3e550c383094b47159f3eee8ffa08e64106cdf5e981be3", [:rebar3], [], "hexpm", "f278585650aa581986264638ebf698f8bb19df297f66ad91b18910dfc6e19323"},
   "parse_trans": {:hex, :parse_trans, "3.3.1", "16328ab840cc09919bd10dab29e431da3af9e9e7e7e6f0089dd5a2d2820011d8", [:rebar3], [], "hexpm", "07cd9577885f56362d414e8c4c4e6bdf10d43a8767abb92d24cbe8b24c54888b"},
-  "poison": {:hex, :poison, "4.0.1", "bcb755a16fac91cad79bfe9fc3585bb07b9331e50cfe3420a24bcc2d735709ae", [:mix], [], "hexpm", "ba8836feea4b394bb718a161fc59a288fe0109b5006d6bdf97b6badfcf6f0f25"},
+  "poison": {:hex, :poison, "6.0.0", "9bbe86722355e36ffb62c51a552719534257ba53f3271dacd20fbbd6621a583a", [:mix], [{:decimal, "~> 2.1", [hex: :decimal, repo: "hexpm", optional: true]}], "hexpm", "bb9064632b94775a3964642d6a78281c07b7be1319e0016e1643790704e739a2"},
   "ssl_verify_fun": {:hex, :ssl_verify_fun, "1.1.6", "cf344f5692c82d2cd7554f5ec8fd961548d4fd09e7d22f5b62482e5aeaebd4b0", [:make, :mix, :rebar3], [], "hexpm", "bdb0d2471f453c88ff3908e7686f86f9be327d065cc1ec16fa4540197ea04680"},
   "unicode_util_compat": {:hex, :unicode_util_compat, "0.7.0", "bc84380c9ab48177092f43ac89e4dfa2c6d62b40b8bd132b1059ecc7232f9a78", [:rebar3], [], "hexpm", "25eee6d67df61960cf6a794239566599b09e17e668d3700247bc498638152521"},
 }