Grin v3.0.0: Changes & Improvements

WORK IN PROGRESS

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Introduction

This document outlines changes and improvements in /grin and /grin-wallet as part of the forthcoming v3.0.0, occurring at block height 524,160 (expected Jan 15 2020).

Actions required

If you're a...	...please ensure that you...
Mining software developer	add compatibility for the new Cuckaroom29 Proof of Work.
Miner mining the ASIC resistant proof of work	have a Cuckaroom29 miner installed and a mechanism to switch over at hard fork height.
Exchange
Wallet software developer	Update to use 3.0.0 versions of grin and grin-wallet
End user

Description of changes

Breaking changes

Title	Description
New GPU-targeted proof of work	Cuckaroom, details here.
Enable faster sync

Node improvements

Title	Description
Node API v2
Read header_head and sync_head from header MMRs directly
Refactor transaction building combinators
TUI Logs view	Display logs from within the node TUI
fix: split state validation status into kernel and rproof updates

Wallet improvements

Generally, the v3.0.0 wallet can exchange transactions with v2.x.x series wallets, with a few small caveats around the use of new features. Please see the wallet changes tracking issue for more detail.

Overview of new features

Title	Description
TOR support	Sending and receiving transaction slates using Hidden Services via the TOR network.
Payment proofs	Ability to prove to a recipient that a transaction was made.
Transaction update rework	Ensure wallet state updates are more robust and changes to how the UTXO set is scanned.

Please refer to https://github.com/mimblewimble/grin-wallet/issues/262 for a precise list of all wallet changes and enhancements.

FAQ

Do I need to do something with my grins?

No, they are unaffected.

Will I get additional grins as part of this hard fork?

No, it's a network upgrade, and the network is not expected to split.

Additional Resources

Title	URL
Communication timelines	https://forum.grin.mw/t/grin-v3-0-0-hard-fork-upgrade-jan-2020/6036
Planning issue	https://github.com/mimblewimble/grin-pm/issues/204
Node Milestone	https://github.com/mimblewimble/grin/milestone/15
Wallet Milsetone	https://github.com/mimblewimble/grin-wallet/milestone/6