diff --git a/mix.exs b/mix.exs
index 0c65c74be..64f96b29c 100644
--- a/mix.exs
+++ b/mix.exs
@@ -202,8 +202,7 @@ defp deps do
       {:ex_machina, "~> 2.4", only: :test},
       {:credo, "~> 1.6", only: [:dev, :test], runtime: false},
       {:mock, "~> 0.3.5", only: :test},
-      # temporary downgrade for excoveralls, hackney until hackney max_connections bug will be fixed
-      {:excoveralls, "0.12.3", only: :test},
+      {:excoveralls, "0.15.1", only: :test},
       {:mox, "~> 1.0", only: :test},
       {:websockex, "~> 0.4.3", only: :test}
     ] ++ oauth_deps()
diff --git a/mix.lock b/mix.lock
index 1af08a896..605b0235f 100644
--- a/mix.lock
+++ b/mix.lock
@@ -39,7 +39,7 @@
   "ex_doc": {:hex, :ex_doc, "0.29.1", "b1c652fa5f92ee9cf15c75271168027f92039b3877094290a75abcaac82a9f77", [:mix], [{:earmark_parser, "~> 1.4.19", [hex: :earmark_parser, repo: "hexpm", optional: false]}, {:makeup_elixir, "~> 0.14", [hex: :makeup_elixir, repo: "hexpm", optional: false]}, {:makeup_erlang, "~> 0.1", [hex: :makeup_erlang, repo: "hexpm", optional: false]}], "hexpm", "b7745fa6374a36daf484e2a2012274950e084815b936b1319aeebcf7809574f6"},
   "ex_machina": {:hex, :ex_machina, "2.7.0", "b792cc3127fd0680fecdb6299235b4727a4944a09ff0fa904cc639272cd92dc7", [:mix], [{:ecto, "~> 2.2 or ~> 3.0", [hex: :ecto, repo: "hexpm", optional: true]}, {:ecto_sql, "~> 3.0", [hex: :ecto_sql, repo: "hexpm", optional: true]}], "hexpm", "419aa7a39bde11894c87a615c4ecaa52d8f107bbdd81d810465186f783245bf8"},
   "ex_syslogger": {:hex, :ex_syslogger, "1.5.2", "72b6aa2d47a236e999171f2e1ec18698740f40af0bd02c8c650bf5f1fd1bac79", [:mix], [{:poison, ">= 1.5.0", [hex: :poison, repo: "hexpm", optional: true]}, {:syslog, "~> 1.1.0", [hex: :syslog, repo: "hexpm", optional: false]}], "hexpm", "ab9fab4136dbc62651ec6f16fa4842f10cf02ab4433fa3d0976c01be99398399"},
-  "excoveralls": {:hex, :excoveralls, "0.12.3", "2142be7cb978a3ae78385487edda6d1aff0e482ffc6123877bb7270a8ffbcfe0", [:mix], [{:hackney, "~> 1.0", [hex: :hackney, repo: "hexpm", optional: false]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: false]}], "hexpm", "568a3e616c264283f5dea5b020783ae40eef3f7ee2163f7a67cbd7b35bcadada"},
+  "excoveralls": {:hex, :excoveralls, "0.15.1", "83c8cf7973dd9d1d853dce37a2fb98aaf29b564bf7d01866e409abf59dac2c0e", [:mix], [{:hackney, "~> 1.16", [hex: :hackney, repo: "hexpm", optional: false]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: false]}], "hexpm", "f8416bd90c0082d56a2178cf46c837595a06575f70a5624f164a1ffe37de07e7"},
   "fast_html": {:hex, :fast_html, "2.0.5", "c61760340606c1077ff1f196f17834056cb1dd3d5cb92a9f2cabf28bc6221c3c", [:make, :mix], [{:elixir_make, "~> 0.4", [hex: :elixir_make, repo: "hexpm", optional: false]}, {:nimble_pool, "~> 0.2.0", [hex: :nimble_pool, repo: "hexpm", optional: false]}], "hexpm", "605f4f4829443c14127694ebabb681778712ceecb4470ec32aa31012330e6506"},
   "fast_sanitize": {:hex, :fast_sanitize, "0.2.3", "67b93dfb34e302bef49fec3aaab74951e0f0602fd9fa99085987af05bd91c7a5", [:mix], [{:fast_html, "~> 2.0", [hex: :fast_html, repo: "hexpm", optional: false]}, {:plug, "~> 1.8", [hex: :plug, repo: "hexpm", optional: false]}], "hexpm", "e8ad286d10d0386e15d67d0ee125245ebcfbc7d7290b08712ba9013c8c5e56e2"},
   "file_system": {:hex, :file_system, "0.2.10", "fb082005a9cd1711c05b5248710f8826b02d7d1784e7c3451f9c1231d4fc162d", [:mix], [], "hexpm", "41195edbfb562a593726eda3b3e8b103a309b733ad25f3d642ba49696bf715dc"},