diff --git a/.github/workflows/quicktest.yml b/.github/workflows/quicktest.yml
index 7600074..11d1530 100644
--- a/.github/workflows/quicktest.yml
+++ b/.github/workflows/quicktest.yml
@@ -59,6 +59,10 @@ jobs:
         if: ${{ matrix.phpcs_version != 'lowest' }}
         run: composer require squizlabs/php_codesniffer:"${{ matrix.phpcs_version }}" --no-update --no-scripts --no-interaction
 
+      - name: "Composer: use lock file when necessary"
+        if: ${{ matrix.phpcs_version == 'lowest' }}
+        run: composer config --unset lock
+
       # Install dependencies and handle caching in one go.
       # @link https://github.com/marketplace/actions/install-php-dependencies-with-composer
       - name: Install Composer dependencies
diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 45f68d4..c8d0ba0 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -65,6 +65,10 @@ jobs:
         if: ${{ matrix.phpcs_version != 'lowest' }}
         run: composer require squizlabs/php_codesniffer:"${{ matrix.phpcs_version }}" --no-update --no-scripts --no-interaction
 
+      - name: "Composer: use lock file when necessary"
+        if: ${{ matrix.phpcs_version == 'lowest' }}
+        run: composer config --unset lock
+
       # Install dependencies and handle caching in one go.
       # @link https://github.com/marketplace/actions/install-php-dependencies-with-composer
       - name: Install Composer dependencies
@@ -133,6 +137,10 @@ jobs:
         if: ${{ matrix.phpcs_version != 'lowest' }}
         run: composer require squizlabs/php_codesniffer:"${{ matrix.phpcs_version }}" --no-update --no-scripts --no-interaction
 
+      - name: "Composer: use lock file when necessary"
+        if: ${{ matrix.phpcs_version == 'lowest' }}
+        run: composer config --unset lock
+
       # Install dependencies and handle caching in one go.
       # @link https://github.com/marketplace/actions/install-php-dependencies-with-composer
       - name: Install Composer dependencies
diff --git a/composer.json b/composer.json
index 9212257..28617b0 100644
--- a/composer.json
+++ b/composer.json
@@ -64,6 +64,7 @@
     "config": {
         "allow-plugins": {
             "dealerdirect/phpcodesniffer-composer-installer": true
-        }
+        },
+        "lock": false
     }
 }