public function isModuleActive($sModuleId, $sVersionFrom = null, $sVersionTo = null)
    {
        $blModuleIsActive = false;

        // use aModuleVersions instead of aModules, because aModules gives only modules which extend oxid classes
        $aModuleVersions = $this->getConfig()->getConfigParam('aModuleVersions');

        if (is_array($aModuleVersions)) {
            $blModuleIsActive = $this->_moduleExists($sModuleId, $aModuleVersions);

            if ($blModuleIsActive) {
                $blModuleIsActive = $this->_isModuleEnabled($sModuleId) && $this->_isModuleVersionCorrect($sModuleId, $sVersionFrom, $sVersionTo);
            }
        }

        return $blModuleIsActive;
    }