Coin Dance

Revised DAA (w/ PID control)

 Bitcoin ABC | Bitcoin XT

Revise Difficulty Adjustment Algorithm to further improve block times using a new PID control algorithm

Double Spend Notifications

New Bitcoin Cash network message for notifying nodes when an attempted double spend of an unconfirmed transaction has occurred.

Bobtail

A Proof-of-Work Target that Minimizes Blockchain Mining Variance

One Way Aggregate Signatures

 Electron Cash

A non-interactive fungibility solution for transactional privacy.

Switch standard denomination to 'bits'

Switch the standard denomination of Bitcoin Cash to 'bits' (1 millionth of a Bitcoin) and switch the ticker from 'BCH' to 'BIT'.

Representative Tokens (GROUP)

 Bitcoin Unlimited

Enable representative tokens via GROUP

Chain ID

 Bitcoin ABC | nChain | Electron Cash

A simple, yet powerful way to provide more human friendly front ends. The main use is to identify the user by name -or nickname- and mobile phone so wallets have data from users and users can pay to human understandable names instead of cryptographic hashes.

Avalanche

 Team Rocket

A novel metastable consensus protocol family for cryptocurrencies.

Recursive Smelting

A Token Layer Protocol on Bitcoin Cash

Improved 0-conf via security deposits

 Bitcoin Unlimited

the consumer will make a special ZCF transaction that pays the merchant and simultaneously posts a security deposit. If the transaction is honest, the consumer can later reclaim his deposit. If he tries to double spend, he necessarily reveals a second signature over the same public key which is then used by miners to claim his deposit for themselves. Pretty clever!

UTXO commitments

 Bitcoin ABC | bitCrust

The construction of a 32-byte hash that is uniquely defined for a UTXO set, that is, the set of all unspent transaction outputs that exist at a certain block in the blockchain

BUIP087 nomenclature for 1/1,000,000 BCH

 Bitcoin Unlimited

Add "cash" in addition to "bit" as a term for 100 (one hundred) satoshi or 1/1,000,000 (one one-millionth) of a bitcoin cash BCH (i.e. 0.000001 BCH). Further, we propose the unofficial ISO code "XCH" to represent a cash unit (millionth of a BCH unit). -- UPDATE: For French translations only.

Modified fee structure

 Bitcoin ABC

Modified fee structure to allow for an order of magnitude decrease in fees for typical transactions (not strictly a consensus change, but an important change being included with the release).

Canonical Transaction Ordering

 Bitcoin ABC | Bitcoin XT

With the exception of the coinbase transaction, transactions within a block must be sorted in numerically ascending order of the transaction id. This proposal is also known as Lexical Transaction Order. It simultaneously removes the existing Topological Transaction Order constraint.

Enforce minimum transaction size

 Bitcoin ABC

Transactions that are smaller than 100 bytes shall be considered invalid. This protects against a Merkle tree vulnerability that allows attackers to spoof transactions against SPV wallets.

Enforce Push-Only for scriptSig

 Bitcoin ABC

Transactions shall be considered invalid if an opcode with number greater than 96 (hex encoding 0x60) appears in a scriptSig.

Increase the max block size to 128MB

 nChain

Consider all blocks in size up to 128MB to be valid.

Restore OP Codes (MUL, SHIFT, INVERT)

 nChain

Re-activate the following additional opcodes: OP_MUL, OP_LSHIFT, OP_RSHIFT, and OP_INVERT.

Script Instructions Restriction

 nChain

Loosen the restriction on the number of instructions executed per script (currently 201) to 500.

OP_CHECKDATASIG

 Bitcoin Unlimited | Bitcoin ABC

OP_CHECKDATASIG and OP_CHECKDATASIGVERIFY check whether a signature is valid with respect to a message and a public key. OP_CHECKDATASIG permits data to be imported into a script, and have its validity checked against some signing authority such as an "Oracle".

Clean Stack

 Bitcoin ABC

For a transaction to be valid, only a single non-zero item must remain on the stack upon completion of Script evaluation. If any extra data elements remain on the stack, the script evaluates to false. This is the same as BIP 62 rule #6.

Base32 addresses

 Bitcoin ABC | Bitcoin XT | Copay (Bitpay)

Support Base32 address format

Revised DAA

 Bitcoin ABC | Bitcoin XT

Revise Difficulty Adjustment Algorithm

Graphene

 Bitcoin Unlimited

An efficient method of announcing new blocks

Re-enable Satoshi Opcodes

 Bitcoin ABC | nChain

Re-enable the previously disabled opcodes which were part of the original Bitcoin design. This should enable smart contract compilers, and a variety of functionality on Bitcoin Cash.

Default to 32MB blocks

 Bitcoin ABC

Start accepting blocks up to 32MB by default.

Increase default datacarriersize to 220 bytes

 Bitcoin ABC

To disincentivize the use of other methods to embed data into the chain, in particular via P2SH, the default datacarriersize is raised from 80 byte to 220 bytes, so it becomes the "cheapest" way of embedding data into the chain.

Double spend proof creation and forwarding

 Bitcoin Unlimited

Update to inform other nodes of double spend attempts immediately to improve the reliability of 0-conf transactions.

Generalized version bits voting (BIP 135)

 Bitcoin Unlimited

BIP 135 extends the semantics of the signaling bits to cover arbitrary consensus changes, referred to under the general term 'forks'. The same range of version bits is used for signaling.