The Filecoin v21 "Watermelon" Network Upgrade, which happened on the 2023-12-12T13:30:00Z at epoch 3469380, introduces vital improvements and new features, aiming to enhance the network's efficiency, security, and overall functionality. This upgrade includes several critical FIPs, each focusing on a specific aspect of the network, contributing to its robustness and adaptability. These improvements are designed to optimice the experience for both storage providers and users, reflecting Filecoin's commitment to continuous evolution and technological advancement.

Here's a breakdown of each proposed FIP:

FIP-0052: Increase Max Sector Commitment to 3.5 Years

This FIP proposes to increase the maximum sector commitment duration to 3.5 years. The extension is intended to provide more flexibility for storage providers in managing their sectors and investments.

FIP-0059: Synthetic PoRep (Proof of Replication)

This introduces a 'Synthetic Proof of Replication' to reduce onboarding costs for storage providers. It aims to create a more efficient method for proving storage without compromising network security.

FIP-0071: Deterministic State Access (IPLD Reachability)

Focusing on improving the determinism of state access in Filecoin. This change will enhance the reliability and predictability of interacting with the network's state, especially for complex operations.

FIP-0072: Improved Event Syscall API

This proposal aims to improve the event syscall API within the Filecoin Virtual Machine (FVM), making it more efficient and user-friendly for developers.

FIP-0073: Remove Beneficiary from the Self_Destruct Syscall

FIP-0073 suggests removing the beneficiary aspect from the self_destruct syscall. This change is expected to simplify the syscall's operation, enhancing the overall efficiency of the FVM.

FIP-0075: Improvements to FVM Randomness Syscalls

This FIP proposes enhancements to the randomness syscalls in the FVM, which are critical for various network operations. The improvements aim to optimize their performance and reliability.

Fix: Sector Activation Epoch Overwritten by Replica Update

A fix was implemented to correct an issue where the sector activation epochs were being overwritten by replica updates. This fix ensures the accurate tracking of sector activation times, crucial for the network's integrity.The v21 upgrade presents two versions: a mandatory update and an optional one.

The mandatory version, Lotus v1.24.0 (with this highly recommended patch:v1.24.1), includes essential updates for network stability and compliance with the upgrade. The optional version, Lotus v1.25.0 (with this highly recommended patch:v1.25.1,), offers additional features and enhancements that storage providers can choose to implement.

Links
https://github.com/filecoin-project/lotus/releases
https://github.com/filecoin-project/lotus/releases/tag/v1.24.0
https://github.com/filecoin-project/lotus/releases/tag/v1.25.0
https://github.com/filecoin-project/core-devs/blob/master/Network%20Upgrades/v21.md