Due to the gradual implementation of the Core version 0.12.1 by bitcoin companies the system is becoming more stable as the number of “orphan” blocks in it is decreasing.

Orphan blocks are those mined more than once and therefore rejected by the system and not rewarded with bitcoins. The reduction of their number over the last month is attributed to faster block propagation, reads a recent article by NewsBTC.

Indeed, the stats show that since 15 April when the new Core version was issued, only 5 orphan blocks have been mined, not more than one orphan block a day. It is a great improvement comparing with the previous period from mid-March to mid-April when 11 such blocks appeared. Even more used to be created earlier, the number sometimes reaching 5-7 a day. 

When a block is mined, it is included into the blockchain and the miner gets a reward (which currently equals 25 bitcoins, with a halving of the reward expected this summer). But some time should pass between the actual moment when the block is mined and the publication of the corresponding information (the propagation of the block). During that time, other miners continue solving mathematical problems, which can lead to the second mining of the same block.

Reducing the number of orphan blocks is not the only novelty of version 0.12.1. Bitcoin transactions currently may specify a locktime indicating when they may be added to a valid block.

For example, a user can do a money transfer, but the addressee will only be able to receive the money at a certain point in the future.

In this case, the information regarding the transaction would be included not in the earliest generated block, but in the block mined around the locktime of the transaction. 

When a block is generated, the miner can give it a certain "header time", which cannot be later than two hours in the future. The block should have header time greater than the locktime of any transaction in that block.

Apparently, one of the aims of the novelty is distributing burden on blocks more evenly. Nowadays one of the main problems the bitcoin network has to face is the dramatic growth of transactions volume. With the current block size of 1 megabyte, it poses a great challenge to the system.

Andrew Levich