Segwit2x developers: Bitcoin upgrade at block 494,784

Segwit2x developers confirm that the Bitcoin upgrade is to happen at block 494,784
17 August 2017   729

Segregated Witness support has been locked-in as a soft fork expected to activate around August 23rd, 2017 (block height 481,824).

Now Segwit2x developers confirm that the Bitcoin upgrade is to happen at block 494,784.

During the month of November 2017, approximately 90 days after the activation of Segregated Witnesses in the Bitcoin blockchain, a block between 1MB and 2MB in size will be generated by Bitcoin miners in a move to increase network capacity. At this point it is expected that more than 90% of the computational capacity that secures the Bitcoin network will carry on mining on top of this large block.

Jeff Garzik
Segwit2x developer

According to the report, the November 2017 upgrade to 2MB blocks is a hard-fork, but necessary changes are trivial to perform. Some SPV clients are expected to work without any change at all. Most clients will need to tweak only two constants to remain compatible with the new larger blocks:

For SegWit-compatible clients:

  • Maximum block weight doubles from 4,000,000 to 8,000,000
  • Sig-ops per block doubles from 80,000 to 160,000

For non-SegWit-capable clients:

  • Maximum base block size doubles from 1,000,000 to 2,000,000
  • Sig-ops per block doubles from 20,000 to 40,000

Both types of clients should add new DNS seeds:

  • BitPay:
  • OB1:
  • Blockchain:
  • Bloq:


For testing purposes, a new Testnet5 network that builds on the same Genesis block as the existing Testnet3 network has been created, as the report claims. In order to update a client for compatibility with Testnet5, do these changes to existing Testnet3 settings:

  • Port changes from 18333 to 18555.
  • Network magic changes from 0x0b110907 to 0x6e657400
  • BIP-34, BIP-66, BIP-65 and single checkpoint all refer to the block at height 10001 with hash 00000000fb7c0a2aeb5f1244e81921b84b7ac770004543144e10c2284f89bfd8
  • DNS seeds are available at and

Block size/weight and sig-ops changes above also apply to Testnet5.

Compatible Fully-Validating Node Software

Incompatible Fully-Validating Node Software

Bank of China Filed a Patent to Scale Blockchain Systems

Bank of China has filed a patent application for a process able to scale blockchain systems  
23 February 2018   95

According to a document released by China's State Intellectual Property Office (SIPO) on February 23, the application was invented by Zhao Shuxiang and first submitted on September 28 last year.

The application states that instead of letting a new block store transactions from its previous one, a data compressing system could be used to pack transactions from multiple blocks into what the patent calls a "data block."

For example, when the system receives a request to compress transactions from block 1 to 1,000, it causes a new data block to be formed and temporarily hosted on a different storage system. Then, the system will run the packed data through a hash function with a hash value. After that, the compression system will attach labels in order to identify blocks on the blockchain.

With the use of the described method, the patent claims a reduction in the amount of the data stored in new blocks as transactions mount in a blockchain while ensuring that data from all previous transactions will still be tamper-proof and traceable.

At the moment, the patent in the review process.