diff --git a/.github/workflows/bamboo_smtp.yml b/.github/workflows/bamboo_smtp.yml
index bd0ca7a..46c74ea 100644
--- a/.github/workflows/bamboo_smtp.yml
+++ b/.github/workflows/bamboo_smtp.yml
@@ -12,11 +12,13 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        elixir: [1.7.4, 1.8.2, 1.9.1, 1.10.3]
-        otp: [20.3, 21.3, 22.0]
+        elixir: [1.7.4, 1.8.2, 1.9.1, 1.10.3, 1.11.3]
+        otp: [20.3, 21.3, 22.0, 23.0]
         exclude:
           - elixir: 1.10.3
             otp: 20.3
+          - elixir: 1.11.3
+            otp: 20.3
     steps:
       - name: Checkout code
         uses: actions/checkout@v2
diff --git a/mix.exs b/mix.exs
index 667ef8b..02548fb 100644
--- a/mix.exs
+++ b/mix.exs
@@ -30,7 +30,7 @@ defmodule BambooSmtp.Mixfile do
     [
       # core
       {:bamboo, "~> 2.1.0"},
-      {:gen_smtp, "~> 1.1.0"},
+      {:gen_smtp, "~> 1.1.1"},
 
       # dev / test
       {:credo, "~> 1.5.0", only: [:dev, :test]},
diff --git a/mix.lock b/mix.lock
index 5fc462d..6bc24f1 100644
--- a/mix.lock
+++ b/mix.lock
@@ -8,7 +8,7 @@
   "ex_doc": {:hex, :ex_doc, "0.23.0", "a069bc9b0bf8efe323ecde8c0d62afc13d308b1fa3d228b65bca5cf8703a529d", [:mix], [{:earmark_parser, "~> 1.4.0", [hex: :earmark_parser, repo: "hexpm", optional: false]}, {:makeup_elixir, "~> 0.14", [hex: :makeup_elixir, repo: "hexpm", optional: false]}], "hexpm", "f5e2c4702468b2fd11b10d39416ddadd2fcdd173ba2a0285ebd92c39827a5a16"},
   "excoveralls": {:hex, :excoveralls, "0.14.0", "4b562d2acd87def01a3d1621e40037fdbf99f495ed3a8570dfcf1ab24e15f76d", [:mix], [{:hackney, "~> 1.16", [hex: :hackney, repo: "hexpm", optional: false]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: false]}], "hexpm", "94f17478b0cca020bcd85ce7eafea82d2856f7ed022be777734a2f864d36091a"},
   "file_system": {:hex, :file_system, "0.2.10", "fb082005a9cd1711c05b5248710f8826b02d7d1784e7c3451f9c1231d4fc162d", [:mix], [], "hexpm", "41195edbfb562a593726eda3b3e8b103a309b733ad25f3d642ba49696bf715dc"},
-  "gen_smtp": {:hex, :gen_smtp, "1.1.0", "b0c92138f69e2f73e1eb791075e93e952efcbc231a536740749b02a1a57155a3", [:rebar3], [{:hut, "1.3.0", [hex: :hut, repo: "hexpm", optional: false]}, {:ranch, ">= 1.7.0", [hex: :ranch, repo: "hexpm", optional: false]}], "hexpm", "e53a13c4bb662331bdf4aa47f00982ef49ce2b4e5c703240542cb7b28f23546a"},
+  "gen_smtp": {:hex, :gen_smtp, "1.1.1", "bf9303c31735100631b1d708d629e4c65944319d1143b5c9952054f4a1311d85", [:rebar3], [{:hut, "1.3.0", [hex: :hut, repo: "hexpm", optional: false]}, {:ranch, ">= 1.7.0", [hex: :ranch, repo: "hexpm", optional: false]}], "hexpm", "51bc50cc017efd4a4248cbc39ea30fb60efa7d4a49688986fafad84434ff9ab7"},
   "hackney": {:hex, :hackney, "1.17.0", "717ea195fd2f898d9fe9f1ce0afcc2621a41ecfe137fae57e7fe6e9484b9aa99", [:rebar3], [{:certifi, "~>2.5", [hex: :certifi, repo: "hexpm", optional: false]}, {:idna, "~>6.1.0", [hex: :idna, repo: "hexpm", optional: false]}, {:metrics, "~>1.0.0", [hex: :metrics, repo: "hexpm", optional: false]}, {:mimerl, "~>1.1", [hex: :mimerl, repo: "hexpm", optional: false]}, {:parse_trans, "~>3.3", [hex: :parse_trans, repo: "hexpm", optional: false]}, {:ssl_verify_fun, "~>1.1.0", [hex: :ssl_verify_fun, repo: "hexpm", optional: false]}, {:unicode_util_compat, "~>0.7.0", [hex: :unicode_util_compat, repo: "hexpm", optional: false]}], "hexpm", "64c22225f1ea8855f584720c0e5b3cd14095703af1c9fbc845ba042811dc671c"},
   "hut": {:hex, :hut, "1.3.0", "71f2f054e657c03f959cf1acc43f436ea87580696528ca2a55c8afb1b06c85e7", [:"erlang.mk", :rebar, :rebar3], [], "hexpm", "7e15d28555d8a1f2b5a3a931ec120af0753e4853a4c66053db354f35bf9ab563"},
   "idna": {:hex, :idna, "6.1.1", "8a63070e9f7d0c62eb9d9fcb360a7de382448200fbbd1b106cc96d3d8099df8d", [:rebar3], [{:unicode_util_compat, "~>0.7.0", [hex: :unicode_util_compat, repo: "hexpm", optional: false]}], "hexpm", "92376eb7894412ed19ac475e4a86f7b413c1b9fbb5bd16dccd57934157944cea"},