Pimcore\Model\Version::cleanHistory PHP Method

    public function cleanHistory()
    {
        if ($this->getCtype() == "document") {
            $conf = Config::getSystemConfig()->documents->versions;
        } elseif ($this->getCtype() == "asset") {
            $conf = Config::getSystemConfig()->assets->versions;
        } elseif ($this->getCtype() == "object") {
            $conf = Config::getSystemConfig()->objects->versions;
        } else {
            return;
        }
        $days = [];
        $steps = [];
        if (intval($conf->days) > 0) {
            $days = $this->getDao()->getOutdatedVersionsDays($conf->days);
        } else {
            $steps = $this->getDao()->getOutdatedVersionsSteps(intval($conf->steps));
        }
        $versions = array_merge($days, $steps);
        foreach ($versions as $id) {
            $version = Version::getById($id);
            $version->delete();
        }
    }