According to Hurricane Electric an Internet Service Provider, the Internet will run out of its IPv4 version of IP addresses on 2nd February at around 4am. This is only a predicted time based on a rate of IP addresses assigned every hour.
The ISP has also launched a countdown accounts termed as “IPcalypse” on Facebook & Twitter.
IPv4 version of IP addresses supports only 4 billion Unique addresses, which is not enough for Internet as the number of devices are increasing at a rate of over 1 million per hour.
This problem can be solved by using IPv6 version which has 340,282,366,920,938,463,463,374,607,431,768,211,456 (You can call this a Zillion) Unique IP addresses.
Both IPv4 & IPv6 can co-exist despite being largely incompatible. Software and hardware developers are working on transition mechanisms, and most operating systems now install support for IPv6 by default. The IPcalypse campaign by Hurrican Electric is also encouraging other ISPs to change to IPv6.