One to four dot-separated integers identifying the version of this extension. A couple of rules apply to the integers: The integers must be between 0 and 65535, inclusive. Non-zero integers can't start with 0. For example, 032 is invalid because it begins with a zero. They must not be all zero. For example, 0 and 0.0.0.0 are invalid while 0.1.0.0 is valid. Here are some examples of valid versions: