diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
new file mode 100644
index 0000000..54c804d
--- /dev/null
+++ b/.github/workflows/ci.yml
@@ -0,0 +1,38 @@
+name: Elixir CI
+
+on:
+  pull_request:
+    branches:
+      - main
+      - dev
+
+jobs:
+  test:
+    name: Test (Elixir ${{ matrix.elixir }}, OTP ${{ matrix.otp }})
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          - elixir: '1.18.4'
+            otp: '28.0'
+            version-type: 'strict'
+          - elixir: '1.12.0'
+            otp: '24.x'
+            version-type: 'loose'
+    steps:
+      - name: Checkout Repository
+        uses: actions/checkout@v4
+
+      - name: Setup Elixir
+        uses: erlef/setup-beam@v1
+        with:
+          elixir-version: ${{ matrix.elixir }}
+          otp-version: ${{ matrix.otp }}
+          version-type: ${{ matrix.version-type }}
+
+      - name: Install Dependencies
+        run: mix deps.get
+
+      - name: Run Tests
+        run: mix test
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 4be9a25..d3b32ad 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,22 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [Unreleased]
+
+### Added
+
+- Added CI workflow to run tests against supported Elixir versions
+
+### Changed
+
+- Updated minimum supported Elixir version to v1.12
+  - While the library may work with older versions, StreamData supports a
+    minimum of v1.12, so it would be missing the property tests
+
+### Fixed
+
+- Updated timestamp decoding to be backwards-compatible with Elixir v1.12
+
 ## [v1.0.2] - 2025-08-06
 
 ### Fixed
diff --git a/README.md b/README.md
index 0d7bbdf..617bf21 100644
--- a/README.md
+++ b/README.md
@@ -62,7 +62,10 @@ This section explains how to setup the project locally for development.
 
 ### Dependencies
 
-- Elixir `~> 1.7` (OTP 21+)
+- Elixir `~> 1.12` (OTP 24+)
+  - See [Compatibility and
+    deprecations](https://hexdocs.pm/elixir/1.18.4/compatibility-and-deprecations.html)
+    for more information
 
 ### Get the Source
 
diff --git a/lib/msgpack/decoder.ex b/lib/msgpack/decoder.ex
index cf71b7a..c76e037 100644
--- a/lib/msgpack/decoder.ex
+++ b/lib/msgpack/decoder.ex
@@ -233,7 +233,8 @@ defmodule Msgpack.Decoder do
       base_datetime = NaiveDateTime.from_erl!(erlang_datetime)
 
       if nanoseconds > 0 do
-        NaiveDateTime.add(base_datetime, nanoseconds, :nanosecond)
+        microseconds = div(nanoseconds, 1000)
+        %{base_datetime | microsecond: {microseconds, 6}}
       else
         base_datetime
       end
@@ -250,7 +251,8 @@ defmodule Msgpack.Decoder do
       base_datetime = NaiveDateTime.from_erl!(erlang_datetime)
 
       if nanoseconds > 0 do
-        NaiveDateTime.add(base_datetime, nanoseconds, :nanosecond)
+        microseconds = div(nanoseconds, 1000)
+        %{base_datetime | microsecond: {microseconds, 6}}
       else
         base_datetime
       end
diff --git a/mix.exs b/mix.exs
index 161d5f8..acb56b7 100644
--- a/mix.exs
+++ b/mix.exs
@@ -8,7 +8,7 @@ defmodule MsgpackElixir.MixProject do
     [
       app: :msgpack_elixir,
       version: @version,
-      elixir: "~> 1.7",
+      elixir: "~> 1.12",
       start_permanent: Mix.env() == :prod,
       deps: deps(),
       aliases: aliases(),