Model/Statistic.php
public function daysFromInstallation()
    {
        $stat = $this->statisticRepository->getStatByAction(self::FASTLY_INSTALLED_FLAG);

        if (!$stat->getCreatedAt()) {
            return null;
        }
        $installDate = date_create($stat->getCreatedAt());
        $currentDate = date_create($this->dateTime->gmtDate());

        $dateDiff = date_diff($installDate, $currentDate);

        return $dateDiff->days;
    }
public function daysFromInstallation()
    {
        $stat = $this->statisticRepository->getStatByAction(self::FASTLY_INSTALLED_FLAG);

        if (!$stat->getCreatedAt()) {
            return null;
        }
        $installDate = date_create($stat->getCreatedAt());
        $currentDate = date_create($this->dateTime->gmtDate());

        $dateDiff = date_diff($installDate, $currentDate);

        return $dateDiff->days;
    }
Calculates number of days since Fastly module installation

@return mixed|null