diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 70b2735..a1855d8 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -9,7 +9,7 @@ on:
 
 jobs:
   test:
-    runs-on: ubuntu-22.04
+    runs-on: ubuntu-26.04
     env:
       MIX_ENV: test
 
@@ -18,12 +18,12 @@ jobs:
       matrix:
         include:
           - pair:
-              elixir: 1.14.2
-              otp: 25.0
+              elixir: 1.20
+              otp: 29.0
             lint: lint
 
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4
 
       - uses: erlef/setup-beam@v1
         with:
@@ -53,10 +53,10 @@ jobs:
       matrix:
         include:
           - pair:
-              elixir: 1.9.0
-              otp: 21.3.8
+              elixir: 1.15
+              otp: 24.3
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4
 
       - uses: erlef/setup-beam@v1
         with:
diff --git a/README.md b/README.md
index 4cc6bf5..f4384ec 100644
--- a/README.md
+++ b/README.md
@@ -1,8 +1,7 @@
 Tzdata
 ======
 
-[![Build
-Status](https://travis-ci.org/lau/tzdata.svg?branch=master)](https://travis-ci.org/lau/tzdata)
+[![Build Status](https://github.com/lau/tzdata/actions/workflows/ci.yml/badge.svg)](https://github.com/lau/tzdata/actions/workflows/ci.yml)
 [![Hex.pm version](https://img.shields.io/hexpm/v/tzdata.svg)](http://hex.pm/packages/tzdata)
 [![Hex.pm downloads](https://img.shields.io/hexpm/dt/tzdata.svg)](https://hex.pm/packages/tzdata)
 
@@ -23,14 +22,24 @@ iex> Tzdata.tzdata_version
 
 ## Getting started
 
-To use the Tzdata library with Elixir 1.8+, add it to the dependencies in your mix file:
+To use the Tzdata library with Elixir 1.15+, add it to the dependencies in your mix file.
+Tzdata also needs an HTTP client to download timezone data updates: add either
+[Req](https://hex.pm/packages/req) or [Hackney](https://hex.pm/packages/hackney)
+(see the "HTTP client" section below):
 
 ```elixir
 defp deps do
-  [  {:tzdata, "~> 1.1"},  ]
+  [
+    {:tzdata, "~> 1.2"},
+    {:req, "~> 0.7"},
+  ]
 end
 ```
 
+Instead of Req, you can use `{:hackney, "~> 1.17 or ~> 4.0"}`. If automatic data
+updates are disabled (see the "Automatic data updates" section below), no HTTP
+client is needed.
+
 In your application you can choose to globally configure Elixir to use Tzdata.
 This can be done by putting the following line in the config file of your application:
 
@@ -97,9 +106,38 @@ For use with [Calendar](https://github.com/lau/calendar) you can still
 specify tzdata ~> 0.1.7 in your mix.exs file in case you experience problems
 using version ~> 0.5.20
 
-## Hackney dependency and security
+## HTTP client
+
+Tzdata uses an HTTP client to poll IANA for new timezone data releases and download them.
+Both [Req](https://hex.pm/packages/req) and [Hackney](https://hex.pm/packages/hackney) are
+supported out of the box as optional dependencies — add one of them to your mix file:
+
+```elixir
+{:req, "~> 0.7"}
+```
+
+or
+
+```elixir
+{:hackney, "~> 1.17 or ~> 4.0"}
+```
+
+If both are present, Req is preferred. If neither is available and automatic data updates
+are enabled, an error is raised when Tzdata tries to fetch updates.
+
+The client can also be selected explicitly with the `http_client` config option:
+
+```elixir
+config :tzdata, :http_client, Tzdata.HTTPClient.Hackney
+```
+
+The same option can be used to supply a custom client: any module implementing the
+`Tzdata.HTTPClient` behaviour (its `get/3` and `head/3` callbacks).
 
-Tzdata depends on Hackney in order to do HTTPS requests to get new updates. This is done because Erlang's built in HTTP client `httpc` does not verify SSL certificates when doing HTTPS requests. Hackney verifies the certificate of IANA when getting new tzdata releases from IANA.
+An HTTP client that verifies SSL certificates is used instead of Erlang's built in
+HTTP client `httpc`, because `httpc` does not verify SSL certificates when doing
+HTTPS requests. Req and Hackney verify the certificate of IANA when getting new
+tzdata releases from IANA.
 
 ## Documentation
 
diff --git a/lib/tzdata/data_loader.ex b/lib/tzdata/data_loader.ex
index 192dd54..7ba0ed5 100644
--- a/lib/tzdata/data_loader.ex
+++ b/lib/tzdata/data_loader.ex
@@ -81,10 +81,10 @@ defmodule Tzdata.DataLoader do
 
   defp do_latest_file_size_by_head({:error, error}), do: {:error, error}
 
-  defp do_latest_file_size_by_head({_tag, resp_code, _headers}) when resp_code != 200,
+  defp do_latest_file_size_by_head({:ok, {resp_code, _headers}}) when resp_code != 200,
     do: {:error, :did_not_get_ok_response}
 
-  defp do_latest_file_size_by_head({_tag, _resp_code, headers}) do
+  defp do_latest_file_size_by_head({:ok, {_resp_code, headers}}) do
     headers
     |> content_length_from_headers
   end
@@ -170,7 +170,5 @@ defmodule Tzdata.DataLoader do
 
   defp data_dir, do: Tzdata.Util.data_dir()
 
-  defp http_client() do
-    Application.get_env(:tzdata, :http_client, Tzdata.HTTPClient.Hackney)
-  end
+  defp http_client, do: Tzdata.Util.http_client!()
 end
diff --git a/lib/tzdata/http_client/hackney.ex b/lib/tzdata/http_client/hackney.ex
index c6b75e0..c212b19 100644
--- a/lib/tzdata/http_client/hackney.ex
+++ b/lib/tzdata/http_client/hackney.ex
@@ -1,9 +1,9 @@
-defmodule Tzdata.HTTPClient.Hackney do
-  @moduledoc false
+if Code.ensure_loaded?(:hackney) do
+  defmodule Tzdata.HTTPClient.Hackney do
+    @moduledoc false
 
-  @behaviour Tzdata.HTTPClient
+    @behaviour Tzdata.HTTPClient
 
-  if Code.ensure_loaded?(:hackney) do
     @impl true
     def get(url, headers, options) do
       with {:ok, status, headers, result} <- :hackney.get(url, headers, "", options),
@@ -27,29 +27,5 @@ defmodule Tzdata.HTTPClient.Hackney do
         {:ok, {status, headers}}
       end
     end
-  else
-    @message """
-    missing :hackney dependency
-
-    Tzdata requires a HTTP client in order to automatically update timezone
-    database.
-
-    In order to use the built-in adapter based on Hackney HTTP client, add the
-    following to your mix.exs dependencies list:
-
-        {:hackney, "~> 4.0"}
-
-    See README for more information.
-    """
-
-    @impl true
-    def get(_url, _headers, _options) do
-      raise @message
-    end
-
-    @impl true
-    def head(_url, _headers, _options) do
-      raise @message
-    end
   end
 end
diff --git a/lib/tzdata/http_client/req.ex b/lib/tzdata/http_client/req.ex
new file mode 100644
index 0000000..f631aa7
--- /dev/null
+++ b/lib/tzdata/http_client/req.ex
@@ -0,0 +1,52 @@
+if Code.ensure_loaded?(Req) do
+  defmodule Tzdata.HTTPClient.Req do
+    @moduledoc false
+
+    @behaviour Tzdata.HTTPClient
+
+    @impl true
+    def get(url, headers, options) do
+      case Req.get(url, req_options(headers, options)) do
+        {:ok, %Req.Response{status: status, headers: resp_headers, body: body}} ->
+          {:ok, {status, normalize_headers(resp_headers), body}}
+
+        {:error, reason} ->
+          {:error, reason}
+      end
+    end
+
+    @impl true
+    def head(url, headers, options) do
+      case Req.head(url, req_options(headers, options)) do
+        {:ok, %Req.Response{status: status, headers: resp_headers}} ->
+          {:ok, {status, normalize_headers(resp_headers)}}
+
+        {:error, reason} ->
+          {:error, reason}
+      end
+    end
+
+    defp req_options(headers, options) do
+      [
+        headers: headers,
+        redirect: Keyword.get(options, :follow_redirect, false),
+        # The downloaded tar.gz must be returned as-is, so don't send
+        # accept-encoding (on by default in Req < 0.7) and disable Req's
+        # automatic decompression and body decoding.
+        compressed: false,
+        raw: true
+      ]
+    end
+
+    # Req (v0.4+) returns headers as a map of lists.
+    defp normalize_headers(headers) when is_map(headers) do
+      for {name, values} <- headers, value <- values, do: {name, value}
+    end
+
+    # Req has a `legacy_headers_as_lists: true` option, for
+    # backwards-compatibility.
+    defp normalize_headers(headers) when is_list(headers) do
+      headers
+    end
+  end
+end
diff --git a/lib/tzdata/tzdata_app.ex b/lib/tzdata/tzdata_app.ex
index d060e95..6067585 100644
--- a/lib/tzdata/tzdata_app.ex
+++ b/lib/tzdata/tzdata_app.ex
@@ -5,10 +5,17 @@ defmodule Tzdata.App do
 
   def start(_type, _args) do
     children = [Tzdata.EtsHolder]
-    children = case Application.fetch_env(:tzdata, :autoupdate) do
-      {:ok, :enabled} -> children ++ [Tzdata.ReleaseUpdater]
-      {:ok, :disabled} -> children
-    end
+
+    children =
+      case Application.fetch_env!(:tzdata, :autoupdate) do
+        :enabled ->
+          # Getting the HTTP client also ensures that it exists and raises if not.
+          Tzdata.Util.http_client!()
+          children ++ [Tzdata.ReleaseUpdater]
+
+        :disabled ->
+          children
+      end
 
     {:ok, pid} = Supervisor.start_link(children, strategy: :one_for_one)
 
diff --git a/lib/tzdata/util.ex b/lib/tzdata/util.ex
index 76d5bdd..790454d 100644
--- a/lib/tzdata/util.ex
+++ b/lib/tzdata/util.ex
@@ -581,6 +581,47 @@ defmodule Tzdata.Util do
     end
   end
 
+  def http_client! do
+    case Application.get_env(:tzdata, :http_client) do
+      nil ->
+        cond do
+          Code.ensure_loaded?(Tzdata.HTTPClient.Req) -> Tzdata.HTTPClient.Req
+          Code.ensure_loaded?(Tzdata.HTTPClient.Hackney) -> Tzdata.HTTPClient.Hackney
+          true -> nil
+        end
+
+      module ->
+        if Code.ensure_loaded?(module) do
+          module
+        end
+    end
+    |> check_http_client!()
+  end
+
+  defp check_http_client!(module) do
+    if !(module && Code.ensure_loaded?(module)) do
+      raise """
+      missing dependency (or custom HTTP client)
+
+      Tzdata requires a HTTP client in order to automatically update timezone
+      database.
+
+      In order to use a built-in HTTP Client adapter, add the
+      following to your mix.exs dependencies list:
+
+          {:req, "~> 0.7"}
+
+      or
+
+          {:hackney, "~> 4.0"}
+
+      See README for more information, including how to use a custom HTTP Client.
+      """
+    end
+
+    module
+  end
+
   if @elixir_newer_1_12 do
     # See PR #154.
     # Elixir 1.17 and 1.18 deprecated using decreasing Ranges without explicit steps.
diff --git a/mix.exs b/mix.exs
index 0cc8ba1..0b20f26 100644
--- a/mix.exs
+++ b/mix.exs
@@ -1,14 +1,14 @@
 defmodule Tzdata.Mixfile do
   use Mix.Project
 
-  @version "1.1.4"
+  @version "1.2.0"
 
   def project do
     [
       app: :tzdata,
       name: "tzdata",
       version: @version,
-      elixir: "~> 1.9",
+      elixir: "~> 1.15",
       package: package(),
       description: description(),
       deps: deps(),
@@ -27,7 +27,8 @@ defmodule Tzdata.Mixfile do
 
   defp deps do
     [
-      {:hackney, "~> 1.17 or ~> 4.0"},
+      {:req, "~> 0.5", optional: true},
+      {:hackney, "~> 1.17 or ~> 4.0", optional: true},
       {:ex_doc, "~> 0.21", only: :dev, runtime: false}
     ]
   end
@@ -43,8 +44,7 @@ defmodule Tzdata.Mixfile do
   defp env do
     [
       autoupdate: :enabled,
-      data_dir: nil,
-      http_client: Tzdata.HTTPClient.Hackney
+      data_dir: nil
     ]
   end
 
diff --git a/mix.lock b/mix.lock
index c278e8a..d54f934 100644
--- a/mix.lock
+++ b/mix.lock
@@ -2,15 +2,24 @@
   "certifi": {:hex, :certifi, "2.14.0", "ed3bef654e69cde5e6c022df8070a579a79e8ba2368a00acf3d75b82d9aceeed", [:rebar3], [], "hexpm", "ea59d87ef89da429b8e905264fdec3419f84f2215bb3d81e07a18aac919026c3"},
   "earmark_parser": {:hex, :earmark_parser, "1.4.43", "34b2f401fe473080e39ff2b90feb8ddfeef7639f8ee0bbf71bb41911831d77c5", [:mix], [], "hexpm", "970a3cd19503f5e8e527a190662be2cee5d98eed1ff72ed9b3d1a3d466692de8"},
   "ex_doc": {:hex, :ex_doc, "0.37.2", "2a3aa7014094f0e4e286a82aa5194a34dd17057160988b8509b15aa6c292720c", [:mix], [{:earmark_parser, "~> 1.4.42", [hex: :earmark_parser, repo: "hexpm", optional: false]}, {:makeup_c, ">= 0.1.0", [hex: :makeup_c, repo: "hexpm", optional: true]}, {:makeup_elixir, "~> 0.14 or ~> 1.0", [hex: :makeup_elixir, repo: "hexpm", optional: false]}, {:makeup_erlang, "~> 0.1 or ~> 1.0", [hex: :makeup_erlang, repo: "hexpm", optional: false]}, {:makeup_html, ">= 0.1.0", [hex: :makeup_html, repo: "hexpm", optional: true]}], "hexpm", "4dfa56075ce4887e4e8b1dcc121cd5fcb0f02b00391fd367ff5336d98fa49049"},
+  "finch": {:hex, :finch, "0.23.0", "e3f9287ac25a8832f848b144c2b57346aac65b205e2e0629a52adfe6507fd837", [:mix], [{:mime, "~> 1.0 or ~> 2.0", [hex: :mime, repo: "hexpm", optional: false]}, {:mint, "~> 1.8", [hex: :mint, repo: "hexpm", optional: false]}, {:nimble_options, "~> 0.4 or ~> 1.0", [hex: :nimble_options, repo: "hexpm", optional: false]}, {:nimble_pool, "~> 1.1", [hex: :nimble_pool, repo: "hexpm", optional: false]}, {:telemetry, "~> 0.4 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "80e58d3f936f57e3fdf404f83a3642897ae6d9fb642934e46da4d8fe761b99d5"},
   "hackney": {:hex, :hackney, "1.23.0", "55cc09077112bcb4a69e54be46ed9bc55537763a96cd4a80a221663a7eafd767", [:rebar3], [{:certifi, "~> 2.14.0", [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, "3.4.1", [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", "6cd1c04cd15c81e5a493f167b226a15f0938a84fc8f0736ebe4ddcab65c0b44e"},
+  "hpax": {:hex, :hpax, "1.0.4", "777de5d433b0fbdc7c418159c8055910faa8047ffdb3d6b31098d2a46cd7685c", [:mix], [], "hexpm", "afc7cb142ebcc2d01ce7816190b98ce5dd49e799111b24249f3443d730f377ca"},
   "idna": {:hex, :idna, "6.1.1", "8a63070e9f7d0c62eb9d9fcb360a7de382448200fbbd1b106cc96d3d8099df8d", [:rebar3], [{:unicode_util_compat, "~>0.7.0", [hex: :unicode_util_compat, repo: "hexpm", optional: false]}], "hexpm", "92376eb7894412ed19ac475e4a86f7b413c1b9fbb5bd16dccd57934157944cea"},
+  "jason": {:hex, :jason, "1.4.5", "2e3a008590b0b8d7388c20293e9dcc9cf3e5d642fd2a114e4cbbb52e595d940a", [:mix], [{:decimal, "~> 1.0 or ~> 2.0 or ~> 3.0", [hex: :decimal, repo: "hexpm", optional: true]}], "hexpm", "b0c823996102bcd0239b3c2444eb00409b72f6a140c1950bc8b457d836b30684"},
   "makeup": {:hex, :makeup, "1.2.1", "e90ac1c65589ef354378def3ba19d401e739ee7ee06fb47f94c687016e3713d1", [:mix], [{:nimble_parsec, "~> 1.4", [hex: :nimble_parsec, repo: "hexpm", optional: false]}], "hexpm", "d36484867b0bae0fea568d10131197a4c2e47056a6fbe84922bf6ba71c8d17ce"},
   "makeup_elixir": {:hex, :makeup_elixir, "1.0.1", "e928a4f984e795e41e3abd27bfc09f51db16ab8ba1aebdba2b3a575437efafc2", [:mix], [{:makeup, "~> 1.0", [hex: :makeup, repo: "hexpm", optional: false]}, {:nimble_parsec, "~> 1.2.3 or ~> 1.3", [hex: :nimble_parsec, repo: "hexpm", optional: false]}], "hexpm", "7284900d412a3e5cfd97fdaed4f5ed389b8f2b4cb49efc0eb3bd10e2febf9507"},
   "makeup_erlang": {:hex, :makeup_erlang, "1.0.2", "03e1804074b3aa64d5fad7aa64601ed0fb395337b982d9bcf04029d68d51b6a7", [:mix], [{:makeup, "~> 1.0", [hex: :makeup, repo: "hexpm", optional: false]}], "hexpm", "af33ff7ef368d5893e4a267933e7744e46ce3cf1f61e2dccf53a111ed3aa3727"},
   "metrics": {:hex, :metrics, "1.0.1", "25f094dea2cda98213cecc3aeff09e940299d950904393b2a29d191c346a8486", [:rebar3], [], "hexpm", "69b09adddc4f74a40716ae54d140f93beb0fb8978d8636eaded0c31b6f099f16"},
+  "mime": {:hex, :mime, "2.0.7", "b8d739037be7cd402aee1ba0306edfdef982687ee7e9859bee6198c1e7e2f128", [:mix], [], "hexpm", "6171188e399ee16023ffc5b76ce445eb6d9672e2e241d2df6050f3c771e80ccd"},
   "mimerl": {:hex, :mimerl, "1.3.0", "d0cd9fc04b9061f82490f6581e0128379830e78535e017f7780f37fea7545726", [:rebar3], [], "hexpm", "a1e15a50d1887217de95f0b9b0793e32853f7c258a5cd227650889b38839fe9d"},
+  "mint": {:hex, :mint, "1.9.3", "3337184d69179695c7a9f1714d92c11e629d36c8c037a21cf490131d3d150554", [:mix], [{:castore, "~> 0.1.0 or ~> 1.0", [hex: :castore, repo: "hexpm", optional: true]}, {:hpax, "~> 0.1.1 or ~> 0.2.0 or ~> 1.0", [hex: :hpax, repo: "hexpm", optional: false]}], "hexpm", "5f7c9342480c069dbbc4eeac3490303c9e01870ff01a7f1d29b6107054fc1e74"},
+  "nimble_options": {:hex, :nimble_options, "1.1.1", "e3a492d54d85fc3fd7c5baf411d9d2852922f66e69476317787a7b2bb000a61b", [:mix], [], "hexpm", "821b2470ca9442c4b6984882fe9bb0389371b8ddec4d45a9504f00a66f650b44"},
   "nimble_parsec": {:hex, :nimble_parsec, "1.4.2", "8efba0122db06df95bfaa78f791344a89352ba04baedd3849593bfce4d0dc1c6", [:mix], [], "hexpm", "4b21398942dda052b403bbe1da991ccd03a053668d147d53fb8c4e0efe09c973"},
+  "nimble_pool": {:hex, :nimble_pool, "1.1.0", "bf9c29fbdcba3564a8b800d1eeb5a3c58f36e1e11d7b7fb2e084a643f645f06b", [:mix], [], "hexpm", "af2e4e6b34197db81f7aad230c1118eac993acc0dae6bc83bac0126d4ae0813a"},
   "parse_trans": {:hex, :parse_trans, "3.4.1", "6e6aa8167cb44cc8f39441d05193be6e6f4e7c2946cb2759f015f8c56b76e5ff", [:rebar3], [], "hexpm", "620a406ce75dada827b82e453c19cf06776be266f5a67cff34e1ef2cbb60e49a"},
+  "req": {:hex, :req, "0.7.1", "86271f9e29dca83d382222428ced09ba03bad21e24888c50dd4527553d85f642", [:mix], [{:brotli, "~> 0.3.1", [hex: :brotli, repo: "hexpm", optional: true]}, {:finch, "~> 0.21", [hex: :finch, repo: "hexpm", optional: false]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: false]}, {:mime, "~> 2.0.6 or ~> 2.1", [hex: :mime, repo: "hexpm", optional: false]}, {:nimble_csv, "~> 1.0", [hex: :nimble_csv, repo: "hexpm", optional: true]}, {:plug, "~> 1.0", [hex: :plug, repo: "hexpm", optional: true]}], "hexpm", "254638b15ceb9a2624d15aff13bf7903ea2e95cd4b9c1aa18da1fb06e1086b50"},
   "ssl_verify_fun": {:hex, :ssl_verify_fun, "1.1.7", "354c321cf377240c7b8716899e182ce4890c5938111a1296add3ec74cf1715df", [:make, :mix, :rebar3], [], "hexpm", "fe4c190e8f37401d30167c8c405eda19469f34577987c76dde613e838bbc67f8"},
+  "telemetry": {:hex, :telemetry, "1.4.2", "a0cb522801dffb1c49fe6e30561badffc7b6d0e180db1300df759faa22062855", [:rebar3], [], "hexpm", "928f6495066506077862c0d1646609eed891a4326bee3126ba54b60af61febb1"},
   "unicode_util_compat": {:hex, :unicode_util_compat, "0.7.0", "bc84380c9ab48177092f43ac89e4dfa2c6d62b40b8bd132b1059ecc7232f9a78", [:rebar3], [], "hexpm", "25eee6d67df61960cf6a794239566599b09e17e668d3700247bc498638152521"},
 }