diff --git a/lib/tower_rollbar/rollbar/client.ex b/lib/tower_rollbar/rollbar/client.ex
index 0513ce6..4742c7c 100644
--- a/lib/tower_rollbar/rollbar/client.ex
+++ b/lib/tower_rollbar/rollbar/client.ex
@@ -12,10 +12,7 @@ defmodule TowerRollbar.Rollbar.Client do
              Jason.encode!(payload)
            },
            [
-             ssl: [
-               verify: :verify_peer,
-               cacerts: :public_key.cacerts_get()
-             ]
+             ssl: tls_client_options()
            ],
            []
          ) do
@@ -29,6 +26,24 @@ defmodule TowerRollbar.Rollbar.Client do
     end
   end
 
+  if function_exported?(:public_key, :cacerts_get, 0) do
+    # Included in Erlang 25+
+    defp tls_client_options do
+      [
+        verify: :verify_peer,
+        cacerts: :public_key.cacerts_get()
+      ]
+    end
+  else
+    # Support Erlang < 25
+    defp tls_client_options do
+      [
+        verify: :verify_peer,
+        cacertfile: CAStore.file_path()
+      ]
+    end
+  end
+
   defp access_token do
     Application.fetch_env!(:tower_rollbar, :access_token)
   end
diff --git a/mix.exs b/mix.exs
index dafa16c..f4a8e6b 100644
--- a/mix.exs
+++ b/mix.exs
@@ -34,7 +34,8 @@ defmodule TowerRollbar.MixProject do
     [
       {:jason, "~> 1.4"},
       {:tower, github: "mimiquate/tower"},
-      {:plug, "~> 1.16"}
+      {:plug, "~> 1.16"},
+      {:castore, "~> 1.0"}
     ]
   end
 
diff --git a/mix.lock b/mix.lock
index 19fb497..881b395 100644
--- a/mix.lock
+++ b/mix.lock
@@ -1,4 +1,5 @@
 %{
+  "castore": {:hex, :castore, "1.0.7", "b651241514e5f6956028147fe6637f7ac13802537e895a724f90bf3e36ddd1dd", [:mix], [], "hexpm", "da7785a4b0d2a021cd1292a60875a784b6caef71e76bf4917bdee1f390455cf5"},
   "jason": {:hex, :jason, "1.4.1", "af1504e35f629ddcdd6addb3513c3853991f694921b1b9368b0bd32beb9f1b63", [:mix], [{:decimal, "~> 1.0 or ~> 2.0", [hex: :decimal, repo: "hexpm", optional: true]}], "hexpm", "fbb01ecdfd565b56261302f7e1fcc27c4fb8f32d56eab74db621fc154604a7a1"},
   "mime": {:hex, :mime, "2.0.5", "dc34c8efd439abe6ae0343edbb8556f4d63f178594894720607772a041b04b02", [:mix], [], "hexpm", "da0d64a365c45bc9935cc5c8a7fc5e49a0e0f9932a761c55d6c52b142780a05c"},
   "plug": {:hex, :plug, "1.16.0", "1d07d50cb9bb05097fdf187b31cf087c7297aafc3fed8299aac79c128a707e47", [:mix], [{:mime, "~> 1.0 or ~> 2.0", [hex: :mime, repo: "hexpm", optional: false]}, {:plug_crypto, "~> 1.1.1 or ~> 1.2 or ~> 2.0", [hex: :plug_crypto, repo: "hexpm", optional: false]}, {:telemetry, "~> 0.4.3 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "cbf53aa1f5c4d758a7559c0bd6d59e286c2be0c6a1fac8cc3eee2f638243b93e"},