diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index bc2792a..7aa1708 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -14,19 +14,17 @@ jobs:
       fail-fast: false
       matrix:
         include:
-          - otp: "26.0.1"
-            elixir: "1.15.0"
+          # Latest supported versions
+          - otp: "26.2"
+            elixir: "1.15"
             version-type: strict
             dialyzer: true
-
-          - otp: "25.3"
-            elixir: "1.14.3"
             coverage: true
             lint: true
-            version-type: loose
 
-          - otp: "23.0"
-            elixir: "1.11.2"
+          # Oldest supported versions
+          - otp: "21.3"
+            elixir: "1.11.4"
             version-type: loose
 
     env:
@@ -37,9 +35,6 @@ jobs:
       - name: Clone the repository
         uses: actions/checkout@v3
 
-      - name: Start Docker
-        run: docker-compose up --detach
-
       - name: Install OTP and Elixir
         uses: erlef/setup-beam@v1
         with:
@@ -54,14 +49,15 @@ jobs:
           path: |
             deps
             _build
-          key: ${{ runner.os }}-mix-otp${{ matrix.otp }}-elixir${{ matrix.elixir }}-${{ hashFiles('**/mix.lock') }}
+          key: |
+            ${{ runner.os }}-mix-otp${{ matrix.otp }}-elixir${{ matrix.elixir }}-${{ hashFiles('**/mix.lock') }}
+          restore-keys: |
+            ${{ runner.os }}-mix-otp${{ matrix.otp }}-elixir${{ matrix.elixir }}-
 
       - name: Fetch dependencies and verify mix.lock
-        if: steps.cache-deps.outputs.cache-hit != 'true'
         run: mix deps.get --check-locked
 
       - name: Compile dependencies
-        if: steps.cache-deps.outputs.cache-hit != 'true'
         run: mix deps.compile
 
       # Don't cache PLTs based on mix.lock hash, as Dialyzer can incrementally update even old ones
@@ -97,7 +93,7 @@ jobs:
         if: ${{ matrix.lint }}
 
       - name: Run tests
-        run: mix test --trace --exclude propcheck
+        run: mix test --trace
         if: ${{ !matrix.coverage }}
 
       - name: Run tests with coverage
@@ -107,7 +103,3 @@ jobs:
       - name: Run dialyzer
         run: mix dialyzer --format github
         if: ${{ matrix.dialyzer }}
-
-      - name: Dump Docker logs on failure
-        uses: jwalton/gh-docker-logs@v1
-        if: failure()
diff --git a/.gitignore b/.gitignore
index 5215165..407abdd 100644
--- a/.gitignore
+++ b/.gitignore
@@ -27,3 +27,6 @@ ecto_unix_timestamp-*.tar
 
 # SQLite3 databases.
 *.sqlite3
+
+# Dialyzer stuff
+/plts
diff --git a/mix.exs b/mix.exs
index 7b22df5..8596471 100644
--- a/mix.exs
+++ b/mix.exs
@@ -9,7 +9,7 @@ defmodule EctoUnixTimestamp.MixProject do
     [
       app: :ecto_unix_timestamp,
       version: @version,
-      elixir: "~> 1.14",
+      elixir: "~> 1.11",
       start_permanent: Mix.env() == :prod,
       deps: deps(),
       preferred_cli_env: [
diff --git a/test/ecto_unix_timestamp_test.exs b/test/ecto_unix_timestamp_test.exs
index 1991f12..c62147d 100644
--- a/test/ecto_unix_timestamp_test.exs
+++ b/test/ecto_unix_timestamp_test.exs
@@ -2,6 +2,7 @@ defmodule EctoUnixTimestampTest do
   use ExUnit.Case, async: true
 
   import Ecto.Changeset
+  import EctoUnixTimestamp.TestHelpers
 
   defmodule Repo do
     use Ecto.Repo,
@@ -52,7 +53,7 @@ defmodule EctoUnixTimestampTest do
 
   for unit <- [:second, :millisecond, :microsecond] do
     test "timestamps are casted correctly with unit #{inspect(unit)} (utc)" do
-      now = DateTime.utc_now(unquote(unit))
+      now = datetime_utc_now(unquote(unit))
       field = :"timestamp_#{unquote(unit)}_utc"
       params = %{field => DateTime.to_unix(now, unquote(unit))}
 
@@ -64,7 +65,7 @@ defmodule EctoUnixTimestampTest do
     end
 
     test "timestamps are casted correctly with unit #{inspect(unit)} (naive)" do
-      now = NaiveDateTime.utc_now(unquote(unit))
+      now = naive_datetime_utc_now(unquote(unit))
       field = :"timestamp_#{unquote(unit)}_naive"
 
       params = %{
diff --git a/test/test_helper.exs b/test/test_helper.exs
index 869559e..340a20e 100644
--- a/test/test_helper.exs
+++ b/test/test_helper.exs
@@ -1 +1,15 @@
 ExUnit.start()
+
+defmodule EctoUnixTimestamp.TestHelpers do
+  # TODO: remove this once we require Elixir 1.15+, which has DateTime.utc_now/2
+  # which supports built-in truncation.
+  def datetime_utc_now(precision) do
+    DateTime.truncate(DateTime.utc_now(), precision)
+  end
+
+  # TODO: remove this once we require Elixir 1.15+, which has NaiveDateTime.utc_now/2
+  # which supports built-in truncation.
+  def naive_datetime_utc_now(precision) do
+    NaiveDateTime.truncate(NaiveDateTime.utc_now(), precision)
+  end
+end