system/Database/MigrationRunner.php
public function current(string $group = null)
	{
		$this->ensureTable();

		// Set database group if not null
		if (! is_null($group))
		{
			$this->setGroup($group);
		}

		return $this->version($this->currentVersion);
	}
public function current(string $group = null)
	{
		$this->ensureTable();

		// Set database group if not null
		if (! is_null($group))
		{
			$this->setGroup($group);
		}

		return $this->version($this->currentVersion);
	}
Sets the (APP_NAMESPACE) schema to $currentVersion in migration config file

@param string|null $group

@return mixed    Current version string on success, FALSE on failure or no migrations are found