diff --git a/_config/config.yml b/_config/config.yml
index 2c5d726..3826785 100644
--- a/_config/config.yml
+++ b/_config/config.yml
@@ -9,6 +9,9 @@ SilverStripe\Control\Director:
   rules:
     at-taxonomy-overview: Chrometoaster\AdvancedTaxonomies\Controllers\TaxonomyOverviewController
 
+Chrometoaster\AdvancedTaxonomies\Dev\AT4xMigrationTask:
+  enable_v4_migration: true
+
 ---
 Only:
   moduleexists: 'silverstripe/cms'
diff --git a/src/Dev/AT4xMigrationTask.php b/src/Dev/AT4xMigrationTask.php
new file mode 100644
index 0000000..609bd00
--- /dev/null
+++ b/src/Dev/AT4xMigrationTask.php
@@ -0,0 +1,111 @@
+<?php
+
+namespace Chrometoaster\AdvancedTaxonomies\Dev;
+
+use Chrometoaster\AdvancedTaxonomies\Models\BaseObject;
+use Chrometoaster\AdvancedTaxonomies\Models\BaseTerm;
+use Chrometoaster\AdvancedTaxonomies\Models\TaxonomyTerm;
+use Exception;
+use SilverStripe\Control\HTTPRequest;
+use SilverStripe\Core\Config\Config;
+use SilverStripe\Dev\BuildTask;
+use SilverStripe\ORM\DataObject;
+use SilverStripe\ORM\DB;
+use SilverStripe\Versioned\Versioned;
+
+class AT4xMigrationTask extends BuildTask
+{
+    private static $segment = 'AT4x-migration-task';
+
+    protected $title = 'Migrate AT db data from version 3.x to version 4.x';
+
+    protected $description = 'Migrate AT db data from version 3.x to version 4.x';
+
+
+    /**
+     * Static run wrapper with a dummy request
+     *
+     * @throws Exception
+     */
+    public static function migrate()
+    {
+        return self::create()->run(new HTTPRequest('GET', '/'));
+    }
+
+
+    /**
+     * @param HTTPRequest $request
+     * @throws Exception
+     */
+    public function run($request)
+    {
+        if (!Config::forClass(self::class)->get('enable_v4_migration')) {
+            DB::get_schema()->alterationMessage('Data migration to Advanced Taxonomies 4.x format is disabled.', 'notice');
+
+            return;
+        }
+
+        $schema          = DataObject::getSchema();
+        $termTable       = $schema->tableName(TaxonomyTerm::class);
+        $baseObjectTable = $schema->tableName(BaseObject::class);
+        $baseTermTable   = $schema->tableName(BaseTerm::class);
+
+        // Safety net
+        if (!($baseObjectTable && $baseTermTable && $termTable)) {
+            throw new Exception(sprintf("One of the required db tables (%s, %s, %s) doesn't exist, did you run dev/build with a flush param?", $baseObjectTable, $baseTermTable, $termTable));
+        }
+
+        $versionedFields = array_keys(Config::inst()->get(Versioned::class, 'db_for_versions_table'));
+
+        DB::get_conn()->withTransaction(function () use ($schema, $termTable, $versionedFields) {
+
+            // cater for standard versioning db table suffiixes
+            $dbTableSuffixes = [
+                '',
+                '_' . Versioned::LIVE,
+                '_Versions', // add RecordID and Version fields
+            ];
+
+            foreach ($dbTableSuffixes as $dbTableSuffix) {
+                foreach ([BaseObject::class, BaseTerm::class] as $model) {
+
+                    // get db table with suffix and all uninherited db fields
+                    $dbTable = $schema->tableName($model) . $dbTableSuffix;
+                    $dbFields = array_keys($schema->databaseFields($model, false));
+
+                    // add special versioning fields
+                    if ($dbTableSuffix === '_Versions') {
+                        if (get_parent_class($model) === DataObject::class) {
+                            array_push($dbFields, ...$versionedFields);
+                        } else {
+                            array_push($dbFields, 'RecordID', 'Version');
+                        }
+                    }
+
+                    DB::get_schema()->alterationMessage(sprintf('Migrating data to %s table.', $dbTable), 'changed');
+
+                    // make sure the table is empty to avoid foreign key conflicts
+                    DB::query(sprintf('DELETE FROM "%s"', $dbTable));
+
+                    // create a list of unique db table fields
+                    $dbFieldsList = implode('","', array_unique($dbFields));
+
+                    // prepare the insert query
+                    $sql = sprintf(
+                        'INSERT INTO "%s" ("%s") SELECT "%s" FROM "%s"',
+                        $dbTable,
+                        $dbFieldsList,
+                        $dbFieldsList,
+                        $termTable . $dbTableSuffix
+                    );
+
+                    DB::query($sql);
+                }
+            }
+
+            DB::get_schema()->alterationMessage('Taxonomy terms data migrated successfully into Advanced Taxonomies 4.x format.', 'changed');
+        }, function () {
+            DB::get_schema()->alterationMessage('Failed to migrate taxonomy terms data to Advanced Taxonomies 4.x format.', 'error');
+        }, false, true);
+    }
+}
diff --git a/src/Models/BaseObject.php b/src/Models/BaseObject.php
index f3f3102..a39ec28 100644
--- a/src/Models/BaseObject.php
+++ b/src/Models/BaseObject.php
@@ -2,7 +2,9 @@
 
 namespace Chrometoaster\AdvancedTaxonomies\Models;
 
+use Chrometoaster\AdvancedTaxonomies\Dev\AT4MigrationTask;
 use Chrometoaster\AdvancedTaxonomies\Generators\URLSegmentGenerator;
+use SilverStripe\Core\Config\Config;
 use SilverStripe\Forms\FieldList;
 use SilverStripe\Forms\RequiredFields;
 use SilverStripe\i18n\i18n;
@@ -285,4 +287,15 @@ public function providePermissions()
             ],
         ];
     }
+
+
+    /**
+     * Trigger the 3.x to 4.x data migration (when enabled)
+     */
+    public function requireDefaultRecords()
+    {
+        parent::requireDefaultRecords();
+
+        AT4MigrationTask::migrate();
+    }
 }