int getUnixTime(const char T[]) {
  int y = 0, mo = 0, d = 0, h = 0, mi = 0, s = 0;
  sscanf(T, "%d-%d-%dT%d:%d:%d", &y, &mo, &d, &h, &mi, &s);
  struct tm result = {0};
  result.tm_year = y - 1900;
  result.tm_mon = mo - 1;
  result.tm_mday = d;
  result.tm_hour = h;
  result.tm_min = mi;
  result.tm_sec = s;
  long unixTime;
  time_t tt;
  tt = mktime(&result);
  unixTime = tt + UNIX_OFFSET;
  return (int)unixTime;
}

void updateTime2() {
  if ((millis() - t) >= 1000) {
    t = millis();
    time_t now = time(nullptr);
    tm = localtime(&now);
    sprintf(tmbuff, "%02d/%02d/%02d %02d:%02d:%02d", tm->tm_mday, tm->tm_mon + 1, tm->tm_year - 100, tm->tm_hour, tm->tm_min, tm->tm_sec);
    dayStamp = String(tm->tm_year + 1900) + "-" + String(tm->tm_mon + 1) + "-" + String(tm->tm_mday);
    struct tm result = {0};
    result.tm_year = tm->tm_year;
    result.tm_mon = tm->tm_mon;
    result.tm_mday = tm->tm_mday;
    result.tm_hour = tm->tm_hour;
    result.tm_min = tm->tm_min;
    result.tm_sec = tm->tm_sec;
    int unixTime;
    time_t tt;
    tt = mktime(&result);
    timestampUnix = tt + UNIX_OFFSET;
  }
}

void setTimestampUnix() {
  configTime(0, 0, ntp_server); // adjust for your TZ and DST
  while (timestampUnix < 1588689631) {
    delay(1000);
    updateTime2();
  }
  updateTime2();
}