diff --git a/README.md b/README.md
index 35c684c..5680485 100644
--- a/README.md
+++ b/README.md
@@ -10,7 +10,7 @@
 
     ```elixir
     def deps do
-      [{:ueberauth_slack, "~> 0.3"}]
+      [{:ueberauth_slack, "~> 0.4"}]
     end
     ```
 
diff --git a/lib/ueberauth/strategy/slack.ex b/lib/ueberauth/strategy/slack.ex
index c6334bf..5299bd6 100644
--- a/lib/ueberauth/strategy/slack.ex
+++ b/lib/ueberauth/strategy/slack.ex
@@ -28,13 +28,16 @@ defmodule Ueberauth.Strategy.Slack do
   def handle_request!(conn) do
     scopes = conn.params["scope"] || option(conn, :default_scope)
     opts = [ scope: scopes ]
-    if conn.params["state"], do: opts = Keyword.put(opts, :state, conn.params["state"])
-    callback_url = callback_url(conn)
+    opts =
+      if conn.params["state"], do: Keyword.put(opts, :state, conn.params["state"]), else: opts
 
     team = option(conn, :team)
-    if team, do: opts = Keyword.put(opts, :team, team)
+    opts =
+      if team, do: Keyword.put(opts, :team, team), else: opts
 
-    if String.ends_with?(callback_url, "?"), do: callback_url = String.slice(callback_url, 0..-2)
+    callback_url = callback_url(conn)
+    callback_url =
+      if String.ends_with?(callback_url, "?"), do: String.slice(callback_url, 0..-2), else: callback_url
 
     opts = Keyword.put(opts, :redirect_uri, callback_url)
     module = option(conn, :oauth2_module)
@@ -205,9 +208,6 @@ defmodule Ueberauth.Strategy.Slack do
   defp fetch_team(%Plug.Conn{ assigns: %{ ueberauth_failure: _fails }} = conn, _), do: conn
 
   defp fetch_team(conn, token) do
-    auth = conn.private.slack_auth
-    token = conn.private.slack_token
-
     scopes = (token.other_params["scope"] || "")
     |> String.split(",")
 
diff --git a/mix.exs b/mix.exs
index b3ac607..df654ac 100644
--- a/mix.exs
+++ b/mix.exs
@@ -1,21 +1,21 @@
 defmodule UeberauthSlack.Mixfile do
   use Mix.Project
 
-  @version "0.3.0"
+  @version "0.4.0"
 
   def project do
     [app: :ueberauth_slack,
      version: @version,
      name: "Ueberauth Slack",
-     package: package,
-     elixir: "~> 1.1",
+     package: package(),
+     elixir: "~> 1.3",
      build_embedded: Mix.env == :prod,
      start_permanent: Mix.env == :prod,
      source_url: "https://github.com/hassox/ueberauth_slack",
      homepage_url: "https://github.com/hassox/ueberauth_slack",
-     description: description,
-     deps: deps,
-     docs: docs]
+     description: description(),
+     deps: deps(),
+     docs: docs()]
   end
 
   def application do
@@ -25,11 +25,11 @@ defmodule UeberauthSlack.Mixfile do
   defp deps do
     [
       {:oauth2, "0.6.0"},
-      {:ueberauth, "~> 0.2"},
+      {:ueberauth, "~> 0.4"},
 
       # Docs dependencies
-      {:earmark, "~> 0.1", only: :dev},
-      {:ex_doc, "~> 0.1", only: :dev},
+      {:earmark, ">= 0.0.0", only: :dev},
+      {:ex_doc, ">= 0.0.0", only: :dev},
     ]
   end
 
diff --git a/mix.lock b/mix.lock
index 712d06a..f90f2a2 100644
--- a/mix.lock
+++ b/mix.lock
@@ -5,11 +5,12 @@
   "httpoison": {:hex, :httpoison, "0.9.0", "68187a2daddfabbe7ca8f7d75ef227f89f0e1507f7eecb67e4536b3c516faddb", [:mix], [{:hackney, "~> 1.6.0", [hex: :hackney, optional: false]}]},
   "idna": {:hex, :idna, "1.2.0", "ac62ee99da068f43c50dc69acf700e03a62a348360126260e87f2b54eced86b2", [:rebar3], []},
   "metrics": {:hex, :metrics, "1.0.1", "25f094dea2cda98213cecc3aeff09e940299d950904393b2a29d191c346a8486", [:rebar3], []},
+  "mime": {:hex, :mime, "1.0.1", "05c393850524767d13a53627df71beeebb016205eb43bfbd92d14d24ec7a1b51", [:mix], []},
   "mimerl": {:hex, :mimerl, "1.0.2", "993f9b0e084083405ed8252b99460c4f0563e41729ab42d9074fd5e52439be88", [:rebar3], []},
   "mimetype_parser": {:hex, :mimetype_parser, "0.1.2", "221d2d3f727e89d80de5e1610fc2ce444514aa56f873da1b8fc9c033143e5d6a", [:mix], []},
   "oauth2": {:hex, :oauth2, "0.6.0", "f3967aba3f358e64fb70046f659f04ea753d7a407ce032046dd048fc2e2e4be3", [:mix], [{:httpoison, "~> 0.7", [hex: :httpoison, optional: false]}, {:mimetype_parser, "~> 0.1", [hex: :mimetype_parser, optional: false]}, {:poison, "~> 1.3 or ~> 2.0", [hex: :poison, optional: false]}]},
-  "plug": {:hex, :plug, "1.1.3", "2c1b01a51304ab1b88dc4313c0707e69998c8d6d4cdaeef391fa6003b6e31a5a", [:mix], [{:cowboy, "~> 1.0", [hex: :cowboy, optional: true]}]},
+  "plug": {:hex, :plug, "1.2.0", "496bef96634a49d7803ab2671482f0c5ce9ce0b7b9bc25bc0ae8e09859dd2004", [:mix], [{:cowboy, "~> 1.0", [hex: :cowboy, optional: true]}, {:mime, "~> 1.0", [hex: :mime, optional: false]}]},
   "poison": {:hex, :poison, "2.2.0", "4763b69a8a77bd77d26f477d196428b741261a761257ff1cf92753a0d4d24a63", [:mix], []},
   "ssl_verify_fun": {:hex, :ssl_verify_fun, "1.1.0", "edee20847c42e379bf91261db474ffbe373f8acb56e9079acb6038d4e0bf414f", [:rebar, :make], []},
   "ssl_verify_hostname": {:hex, :ssl_verify_hostname, "1.0.5", "2e73e068cd6393526f9fa6d399353d7c9477d6886ba005f323b592d389fb47be", [:make], []},
-  "ueberauth": {:hex, :ueberauth, "0.2.0", "9160c601b468c6692462a56be7ad8890d1a2d84519d7d9c4541da5b07d6495e1", [:mix], [{:plug, "~> 1.0", [hex: :plug, optional: false]}]}}
+  "ueberauth": {:hex, :ueberauth, "0.4.0", "bc72d5e5a7bdcbfcf28a756e34630816edabc926303bdce7e171f7ac7ffa4f91", [:mix], [{:plug, "~> 1.2", [hex: :plug, optional: false]}]}}