diff --git a/CHANGELOG.md b/CHANGELOG.md
index 2461481..abefe15 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,7 +2,7 @@
 
 ## Cldr_Calendars_Ethiopic v1.0.0
 
-This is the changelog for ex_cldr_calendars_ethiopic v1.0.0 released on ____, 2023.  For older changelogs please consult the release tag on [GitHub](https://github.com/elixir-cldr/cldr_calendars_coptic/tags)
+This is the changelog for ex_cldr_calendars_ethiopic v1.0.0 released on April 28th, 2023.  For older changelogs please consult the release tag on [GitHub](https://github.com/elixir-cldr/cldr_calendars_coptic/tags)
 
 **Note that ex_cldr_calendars is now supported on Elixir 1.11 and later**
 
@@ -16,6 +16,8 @@ This is the changelog for ex_cldr_calendars_ethiopic v1.0.0 released on ____, 20
 
 * Bump to version 1.0.0.
 
+* Updates to [ex_cldr version 2.37.0](https://hex.pm/packages/ex_cldr/2.37.0) which includes data from [CLDR release 43](https://cldr.unicode.org/index/downloads/cldr-43).
+
 ## Cldr_Calendars_Ethiopic v0.5.0
 
 This is the changelog for ex_cldr_calendars_ethiopic v0.5.0 released on August 29th, 2021.  For older changelogs please consult the release tag on [GitHub](https://github.com/elixir-cldr/cldr_calendars_ethiopic/tags)
diff --git a/lib/cldr/calendar/ethiopic.ex b/lib/cldr/calendar/ethiopic.ex
index ed7832e..f94e0b1 100644
--- a/lib/cldr/calendar/ethiopic.ex
+++ b/lib/cldr/calendar/ethiopic.ex
@@ -269,6 +269,20 @@ defmodule Cldr.Calendar.Ethiopic do
     30
   end
 
+  @doc """
+  Returns how many days there are in the given month.
+
+  Must be implemented in derived calendars because
+  we cannot know what the calendar format is.
+
+  """
+  @spec days_in_month(Calendar.month) :: Calendar.month() | {:ambiguous, Range.t() | [pos_integer()]} | {:error, :undefined}
+  @impl true
+
+  def days_in_month(_month) do
+    {:error, :undefined}
+  end
+
   @doc """
   Returns the number days in a a week.
 
diff --git a/mix.exs b/mix.exs
index 237a9dd..a6da2f3 100644
--- a/mix.exs
+++ b/mix.exs
@@ -23,14 +23,14 @@ defmodule Cldr.Calendars.Ethiopic.MixProject do
 
   def description do
     """
-    Implementation of the Ethiopic calendar for Elixir
+    Implementation of the Ethiopic calendar for Elixir.
     """
   end
 
   defp package do
     [
       maintainers: ["Kip Cole"],
-      licenses: ["Apache 2.0"],
+      licenses: ["Apache-2.0"],
       logo: "logo.png",
       links: links(),
       files: [
@@ -52,7 +52,7 @@ defmodule Cldr.Calendars.Ethiopic.MixProject do
 
   defp deps do
     [
-      {:ex_cldr_calendars, "~> 1.6"},
+      {:ex_cldr_calendars, "~> 1.22"},
       {:stream_data, "~> 0.4", only: :test},
       {:ex_doc, "~> 0.19", only: [:release, :dev]}
     ]
diff --git a/mix.lock b/mix.lock
index 0f26a5f..0edd3a7 100644
--- a/mix.lock
+++ b/mix.lock
@@ -2,14 +2,14 @@
   "astro": {:hex, :astro, "0.3.0", "6b17a107d2985d87933f6ac89b4fe653009318757b28c769d7d96ab6c73e84da", [:mix], [{:geo, "~> 3.0", [hex: :geo, repo: "hexpm", optional: false]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: false]}, {:tz_world, "~> 0.2", [hex: :tz_world, repo: "hexpm", optional: false]}, {:tzdata, "~> 1.0", [hex: :tzdata, repo: "hexpm", optional: false]}], "hexpm"},
   "certifi": {:hex, :certifi, "2.5.1", "867ce347f7c7d78563450a18a6a28a8090331e77fa02380b4a21962a65d36ee5", [:rebar3], [{:parse_trans, "~>3.3", [hex: :parse_trans, repo: "hexpm", optional: false]}], "hexpm"},
   "cldr_utils": {:hex, :cldr_utils, "2.22.0", "5df60df2603dfeeffe26e40ab1ee565df34da288a53bb2db0d0dbd243fd646ef", [:mix], [{:castore, "~> 0.1 or ~> 1.0", [hex: :castore, repo: "hexpm", optional: true]}, {:certifi, "~> 2.5", [hex: :certifi, repo: "hexpm", optional: true]}, {:decimal, "~> 1.9 or ~> 2.0", [hex: :decimal, repo: "hexpm", optional: false]}], "hexpm", "ea14e8a6aa89ffd59a5d49baebe7ebf852cc024ac50dc2b3dabcd3786eeed657"},
-  "decimal": {:hex, :decimal, "2.0.0", "a78296e617b0f5dd4c6caf57c714431347912ffb1d0842e998e9792b5642d697", [:mix], [], "hexpm", "34666e9c55dea81013e77d9d87370fe6cb6291d1ef32f46a1600230b1d44f577"},
+  "decimal": {:hex, :decimal, "2.1.1", "5611dca5d4b2c3dd497dec8f68751f1f1a54755e8ed2a966c2633cf885973ad6", [:mix], [], "hexpm", "53cfe5f497ed0e7771ae1a475575603d77425099ba5faef9394932b35020ffcc"},
   "digital_token": {:hex, :digital_token, "0.4.0", "2ad6894d4a40be8b2890aad286ecd5745fa473fa5699d80361a8c94428edcd1f", [:mix], [{:cldr_utils, "~> 2.17", [hex: :cldr_utils, repo: "hexpm", optional: false]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: false]}], "hexpm", "a178edf61d1fee5bb3c34e14b0f4ee21809ee87cade8738f87337e59e5e66e26"},
   "earmark": {:hex, :earmark, "1.4.15", "2c7f924bf495ec1f65bd144b355d0949a05a254d0ec561740308a54946a67888", [:mix], [{:earmark_parser, ">= 1.4.13", [hex: :earmark_parser, repo: "hexpm", optional: false]}], "hexpm", "3b1209b85bc9f3586f370f7c363f6533788fb4e51db23aa79565875e7f9999ee"},
   "earmark_parser": {:hex, :earmark_parser, "1.4.31", "a93921cdc6b9b869f519213d5bc79d9e218ba768d7270d46fdcf1c01bacff9e2", [:mix], [], "hexpm", "317d367ee0335ef037a87e46c91a2269fef6306413f731e8ec11fc45a7efd059"},
-  "ex_cldr": {:hex, :ex_cldr, "2.36.0", "ccd7c61c4126aa42d3cd9d93097642930f1b8a10c9c8351fc58bb2c627bad839", [:mix], [{:cldr_utils, "~> 2.21", [hex: :cldr_utils, repo: "hexpm", optional: false]}, {:decimal, "~> 1.6 or ~> 2.0", [hex: :decimal, repo: "hexpm", optional: false]}, {:gettext, "~> 0.19", [hex: :gettext, repo: "hexpm", optional: true]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: true]}, {:nimble_parsec, "~> 0.5 or ~> 1.0", [hex: :nimble_parsec, repo: "hexpm", optional: true]}], "hexpm", "5a56c66cd61ebde42277baa828cd1587959b781ac7e2aee135328a78a4de3fe9"},
-  "ex_cldr_calendars": {:hex, :ex_cldr_calendars, "1.21.0", "5f3c71a145926cfa7f8691aa3566921957543f635ec345e52282c613e8985ba8", [:mix], [{:calendar_interval, "~> 0.2", [hex: :calendar_interval, repo: "hexpm", optional: true]}, {:ex_cldr_lists, "~> 2.10", [hex: :ex_cldr_lists, repo: "hexpm", optional: true]}, {:ex_cldr_numbers, "~> 2.25", [hex: :ex_cldr_numbers, repo: "hexpm", optional: false]}, {:ex_cldr_units, "~> 3.12", [hex: :ex_cldr_units, repo: "hexpm", optional: true]}, {:ex_doc, "~> 0.21", [hex: :ex_doc, repo: "hexpm", optional: true]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: false]}], "hexpm", "8ce8737b70f9c36828324995f96464a1a4c87cf2f76e5868e20662ca31c4098f"},
+  "ex_cldr": {:hex, :ex_cldr, "2.37.0", "3c2957505efb3b721faa365ff80510342f85ca68fb6ca9602ac17a146cda9ee0", [:mix], [{:cldr_utils, "~> 2.21", [hex: :cldr_utils, repo: "hexpm", optional: false]}, {:decimal, "~> 1.6 or ~> 2.0", [hex: :decimal, repo: "hexpm", optional: false]}, {:gettext, "~> 0.19", [hex: :gettext, repo: "hexpm", optional: true]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: true]}, {:nimble_parsec, "~> 0.5 or ~> 1.0", [hex: :nimble_parsec, repo: "hexpm", optional: true]}], "hexpm", "93debfed83043111801108f87df01550ff814d1d59078ba3bf11bf36d46f9063"},
+  "ex_cldr_calendars": {:hex, :ex_cldr_calendars, "1.22.0", "016373c6725682851d752b72585581154926b2c8a20ee43e418479911dae0ff9", [:mix], [{:calendar_interval, "~> 0.2", [hex: :calendar_interval, repo: "hexpm", optional: true]}, {:ex_cldr_lists, "~> 2.10", [hex: :ex_cldr_lists, repo: "hexpm", optional: true]}, {:ex_cldr_numbers, "~> 2.31", [hex: :ex_cldr_numbers, repo: "hexpm", optional: false]}, {:ex_cldr_units, "~> 3.16", [hex: :ex_cldr_units, repo: "hexpm", optional: true]}, {:ex_doc, "~> 0.21", [hex: :ex_doc, repo: "hexpm", optional: true]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: false]}], "hexpm", "c1c86de086009dce5786eb10fed0d351e52a844307c2ff0e83531f91d3268e8b"},
   "ex_cldr_currencies": {:hex, :ex_cldr_currencies, "2.15.0", "aadd34e91cfac7ef6b03fe8f47f8c6fa8c5daf3f89b5d9fee64ec545ded839cf", [:mix], [{:ex_cldr, "~> 2.34", [hex: :ex_cldr, repo: "hexpm", optional: false]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: true]}], "hexpm", "0521316396c66877a2d636219767560bb2397c583341fcb154ecf9f3000e6ff8"},
-  "ex_cldr_numbers": {:hex, :ex_cldr_numbers, "2.30.1", "9acd7adb30079057ba606d73ffdaccb86020b07b734f98a229b5674032181668", [:mix], [{:decimal, "~> 1.6 or ~> 2.0", [hex: :decimal, repo: "hexpm", optional: false]}, {:digital_token, "~> 0.3 or ~> 1.0", [hex: :digital_token, repo: "hexpm", optional: false]}, {:ex_cldr, "~> 2.35", [hex: :ex_cldr, repo: "hexpm", optional: false]}, {:ex_cldr_currencies, ">= 2.14.2", [hex: :ex_cldr_currencies, repo: "hexpm", optional: false]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: true]}], "hexpm", "8a81b63d595a589e72c8b629653755c8b88edd6405a657eba236477f7a85939a"},
+  "ex_cldr_numbers": {:hex, :ex_cldr_numbers, "2.31.0", "c8a3ec332dd4c3276f91f60a163c745efc8233b2d0dd3665102c74cc7c1242e5", [:mix], [{:decimal, "~> 1.6 or ~> 2.0", [hex: :decimal, repo: "hexpm", optional: false]}, {:digital_token, "~> 0.3 or ~> 1.0", [hex: :digital_token, repo: "hexpm", optional: false]}, {:ex_cldr, "~> 2.37", [hex: :ex_cldr, repo: "hexpm", optional: false]}, {:ex_cldr_currencies, ">= 2.14.2", [hex: :ex_cldr_currencies, repo: "hexpm", optional: false]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: true]}], "hexpm", "ca72344451bb2bfbeb6da22b7a45fdc7c38e42d4b9f8a8ed36f8b0072d219c3a"},
   "ex_doc": {:hex, :ex_doc, "0.29.4", "6257ecbb20c7396b1fe5accd55b7b0d23f44b6aa18017b415cb4c2b91d997729", [:mix], [{:earmark_parser, "~> 1.4.31", [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", "2c6699a737ae46cb61e4ed012af931b57b699643b24dabe2400a8168414bc4f5"},
   "geo": {:hex, :geo, "3.3.2", "30c7b458bcb0ab1ca73a997b26d22c68643d9ffe1726e475e0759499b6024cff", [:mix], [], "hexpm"},
   "hackney": {:hex, :hackney, "1.15.2", "07e33c794f8f8964ee86cebec1a8ed88db5070e52e904b8f12209773c1036085", [:rebar3], [{:certifi, "2.5.1", [hex: :certifi, repo: "hexpm", optional: false]}, {:idna, "6.0.0", [hex: :idna, repo: "hexpm", optional: false]}, {:metrics, "1.0.1", [hex: :metrics, repo: "hexpm", optional: false]}, {:mimerl, "~>1.1", [hex: :mimerl, repo: "hexpm", optional: false]}, {:ssl_verify_fun, "1.1.5", [hex: :ssl_verify_fun, repo: "hexpm", optional: false]}], "hexpm"},