diff --git a/.github/workflows/phpunit.yml b/.github/workflows/phpunit.yml
index 969d45d..14212c4 100644
--- a/.github/workflows/phpunit.yml
+++ b/.github/workflows/phpunit.yml
@@ -42,6 +42,9 @@ jobs:
     - name: Check PHP Version
       run: php -v
 
+    - name: Install SVN
+      run: sudo apt-get update && sudo apt-get install -y subversion
+
     - name: Composer install
       run: composer install --optimize-autoloader --prefer-dist
 
diff --git a/admin/class-recursivetable.php b/admin/class-recursivetable.php
index 4f9f35c..7b38311 100644
--- a/admin/class-recursivetable.php
+++ b/admin/class-recursivetable.php
@@ -12,6 +12,8 @@
  * @subpackage Google_Spreadsheet_to_DB/admin
  */
 
+declare(strict_types=1);
+
 /**
  * The core plugin class.
  *
diff --git a/functions/functions.php b/functions/functions.php
index b3ded10..7fc6c05 100644
--- a/functions/functions.php
+++ b/functions/functions.php
@@ -20,6 +20,8 @@
  * @subpackage Google_Spreadsheet_to_DB/functions
  */
 
+declare(strict_types=1);
+
 if ( file_exists( plugin_dir_path( __FILE__ ) . 'composer/vendor/autoload.php' ) ) {
 	require_once plugin_dir_path( __FILE__ ) . 'composer/vendor/autoload.php';
 }
diff --git a/google-spreadsheet-to-db.php b/google-spreadsheet-to-db.php
index f295526..6366d37 100644
--- a/google-spreadsheet-to-db.php
+++ b/google-spreadsheet-to-db.php
@@ -14,6 +14,8 @@
  * @package         Google_Spreadsheet_to_DB
  */
 
+declare(strict_types=1);
+
 $google_ss2db_minimalrequiredphpversion = '8.0';
 
 global $wpdb;
diff --git a/includes/class-google-spreadsheet-to-db-activator.php b/includes/class-google-spreadsheet-to-db-activator.php
index a5f9eea..9c72e17 100755
--- a/includes/class-google-spreadsheet-to-db-activator.php
+++ b/includes/class-google-spreadsheet-to-db-activator.php
@@ -9,6 +9,8 @@
  * @subpackage Google_Spreadsheet_to_DB/functions
  */
 
+declare(strict_types=1);
+
 /**
  * Fired during plugin activation.
  *
diff --git a/includes/class-google-spreadsheet-to-db-query.php b/includes/class-google-spreadsheet-to-db-query.php
index ff2404e..e5af41d 100755
--- a/includes/class-google-spreadsheet-to-db-query.php
+++ b/includes/class-google-spreadsheet-to-db-query.php
@@ -1,14 +1,16 @@
 <?php
-	/**
-	 * This file contains the Google_Spreadsheet_To_DB_Query class which handles SQL queries for the Google Spreadsheet to DB plugin.
-	 *
-	 * The class is designed to construct and execute SQL queries with support for filtering, sorting, and pagination.
-	 * It is initialized with customizable parameters to tailor the query operations.
-	 *
-	 * @package    Google_Spreadsheet_to_DB
-	 * @subpackage Google_Spreadsheet_to_DB/includes
-	 * @since      1.0.2
-	 */
+/**
+ * This file contains the Google_Spreadsheet_To_DB_Query class which handles SQL queries for the Google Spreadsheet to DB plugin.
+ *
+ * The class is designed to construct and execute SQL queries with support for filtering, sorting, and pagination.
+ * It is initialized with customizable parameters to tailor the query operations.
+ *
+ * @package    Google_Spreadsheet_to_DB
+ * @subpackage Google_Spreadsheet_to_DB/includes
+ * @since      1.0.2
+ */
+
+declare(strict_types=1);
 
 /**
  * Handles database queries for the Google Spreadsheet to DB plugin.
diff --git a/includes/index.php b/includes/index.php
index 8cb1cd5..2072e32 100644
--- a/includes/index.php
+++ b/includes/index.php
@@ -12,6 +12,8 @@
  * @subpackage Google_Spreadsheet_to_DB/includes
  */
 
+declare(strict_types=1);
+
 /**
  * The core plugin class.
  *
diff --git a/includes/save.php b/includes/save.php
index 0c38bc2..89c808a 100644
--- a/includes/save.php
+++ b/includes/save.php
@@ -12,6 +12,8 @@
  * @subpackage Google_Spreadsheet_to_DB/includes
  */
 
+declare(strict_types=1);
+
 /**
  * The core plugin class.
  *