51% attack prevention HORIZEN mandatory upgrade to 2.0.15

HoriZen (formerly known as Zencash) was attacked with 51% attack. The team worked on this quickly and released a patch soon while will make 51% attack more difficult & expensive to carry on. This is a mandatory upgrade for all, specially node operators as they will miss potential payouts. In this video I have explained how to upgrade your secure node so that you don''t miss your payouts