code: protected String toHexString(boolean with0xPrefix, CharSequence zone) {
  		if(isDualString()) {
  			return toNormalizedStringRange(toIPParams(with0xPrefix ? IPStringCache.hexPrefixedParams : IPStringCache.hexParams), getLower(), getUpper(), zone);
  		}
  		return toIPParams(with0xPrefix ? IPStringCache.hexPrefixedParams : IPStringCache.hexParams).toString(this, zone);
  	}
docs: overridden in ipv6 to handle zone