We say, IPv4 is depleting! but what about Class E addresses?

                                            
As per our basic knowledge of IP addresses,  they are divided into 5 classes i.e. from A to E. Class A,B & C addresses are used for general unicast addressing whereas Class D is used for multicast addressing and Class E was reserved for the future use.

There were two drafts proposed for resolving this situation. According to these two drafts, at the present time, most IP implementations consider any IP address in the range 240.0.0.0 through 255.255.255.255 to be invalid as the source or destination of a datagram. The check for such "illegal" addresses may occur in many places, including at datagram receipt, before IP datagram transmission, when an IP address is assigned to a network interface, or even by router and firewall configuration parsers.

Also the TCP/IP stack in Windows do not support Class E address so they were not in the position to communicate with each other.