Filecoin Network v16 'Skyr' Upgrade - FAQ from Community AMA!

[kaitlin-beegle]

On July 6, at epoch 1960320, the Filecoin network will be upgraded to version 16: the Skyr network. This network will introduce a series of enhancements, bug fixes, and new FIPs, including those supporting the Filecoin Virtual Machine.

In preparation, the community held an AMA with implementors, Core Devs, and FVM engineers in Filecoin Project Slack. Below is a FAQ list with the most popular questions and answers!

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Q: Which version of Lotus will run the FVM?
A: Both Lotus versions v1.16.0 and v1.17.0 will support the FVM. Both versions are currently available as release candidates; full versions will be released prior to the July 6 upgrade.

Q: When do I need to upgrade to the latest version of Lotus?
A: You will need to have upgraded your node by the epoch 1960320, which will occur at approximately 14:00 UTC on July 6th, 2022. For the official network upgrade notice, please see HERE. For the community network discussion, please see HERE.

Q: Will the FVM impact gas fees or network throughput?
A: Yes and no. With the FVM introducing a WASM bytecode, the network will now be able to price the actual cost of execution of actor/smart contract logic. To support this, FIP0032 introduced three new gas elements: execution gas, syscall gas, and extern gas. Network base fee- which calculates gas costs- will remain unchanged. However, to ensure no spike in base fee during the introduction of the FVM, new gas parameters were tested extensively by the FVM engineering team (see: HERE and HERE). The CrytpoEconLab also performed an analysis to ensure the continued stability of the network.

Q: What work are we doing to support FVM <> EVM compatibility?
A: Many community members have indicated that EVM compatibility is a significant priority. As such, EVM compatibility will now be shipped as FVM milestone M2.1 in the autumn of 2022. This work will bedeployed incrementally, in testnets, with the support of community partners. The FVM team has already completed a significant amount of research and has a working EVM bytecode execution! A high-level demo will be delivered at FIL Toronto.

Q: Will EVM actors be able to dispatch methods to native FVM builtin actors? What functionality isn’t available to EVM actors that would be available to FVM actors?
A: EVM actors can call FVM actors, and vice versa. All actors will interface in the same way, and additional Solidity libraries are already being prepared to reduce friction between actors. The primary difference in functionality is that the FVM is additionally able to provide an actor “upgrade” capability and is able to make better use of existing IPLD functionalities. For example, the FVM will be able to cheaply send an immutable copy of its state-tree to another actor, which the EVM cannot do. Though some of these features can be made available to EVM actors through precompiles, their usefulness and limitations will need to be further studied on a case-by-case basis.

Q: Are there any new security vulnerabilities that need to be considered when forking a contract from an EVM blockchain to an FVM actor?
A: No. To prevent security vulnerabilities from arising, there is a ‘double’ sandbox in place: the EVM sandbox, and the FVM/WASM sandbox. However, it is important to remember that bugs can occur at any level. We also need to be mindful of potential “dissonances”, or mismatches, between EVM and FVM/WASM that could create gray zones.