diff --git a/mix.exs b/mix.exs
index 0b0422d..3b48628 100644
--- a/mix.exs
+++ b/mix.exs
@@ -69,7 +69,7 @@ defmodule RDF.Mixfile do
   defp deps do
     [
       {:decimal, "~> 1.5"},
-      {:protocol_ex, "~> 0.4"},
+      {:protocol_ex, "~> 0.4.4"},
       {:credo, "~> 1.5", only: [:dev, :test], runtime: false},
       {:dialyxir, "~> 1.1", only: [:dev, :test], runtime: false},
       {:ex_doc, "~> 0.24", only: :dev, runtime: false},
diff --git a/mix.lock b/mix.lock
index d134858..b4a0b6a 100644
--- a/mix.lock
+++ b/mix.lock
@@ -21,7 +21,7 @@
   "mimerl": {:hex, :mimerl, "1.2.0", "67e2d3f571088d5cfd3e550c383094b47159f3eee8ffa08e64106cdf5e981be3", [:rebar3], [], "hexpm", "f278585650aa581986264638ebf698f8bb19df297f66ad91b18910dfc6e19323"},
   "nimble_parsec": {:hex, :nimble_parsec, "1.1.0", "3a6fca1550363552e54c216debb6a9e95bd8d32348938e13de5eda962c0d7f89", [:mix], [], "hexpm", "08eb32d66b706e913ff748f11694b17981c0b04a33ef470e33e11b3d3ac8f54b"},
   "parse_trans": {:hex, :parse_trans, "3.3.1", "16328ab840cc09919bd10dab29e431da3af9e9e7e7e6f0089dd5a2d2820011d8", [:rebar3], [], "hexpm", "07cd9577885f56362d414e8c4c4e6bdf10d43a8767abb92d24cbe8b24c54888b"},
-  "protocol_ex": {:hex, :protocol_ex, "0.4.3", "4acbe35da85109dc40315c1139bb7a65ebc7fc102d384cd8b3038384fbb9b282", [:mix], [], "hexpm", "6ca5ddb3505c9c86f17cd3f19838b34bf89966ae17078f79f81983b6a4391fe9"},
+  "protocol_ex": {:hex, :protocol_ex, "0.4.4", "c9717d1c0bdabe37d7653965dc02e78580d0d06a1f86d737b7941b55241f70d6", [:mix], [], "hexpm", "2b78ed0e5ec76f62b0debaf92dc8e795551cdaf7fc22b8816b3d57225020ac99"},
   "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"},
 }