Cadence 1.0

The most intuitive and powerful programming language to write safe smart contracts

Cadence 1.0

Elevated Developer Experience

View functions transform your code with enhanced reliability and safety. Clearly distinguish between state-changing and state-preserving functions, and anotate for better predictability.

Improved Safety and Security

With the Cadence 1.0, it streamline the usage of Capabilities and introducing Entitlements to make Cadence secure by default and removes previously confusing “foot-guns”.

Faster & Easier Composability

With composability at the heart of Cadence, “Attachments” make standard, and permissionless composability native on Flow.

And Many More Foundational Improvements...

Cadence 1.0 Migration Hub

Cadence 1.0 Upgrade: Everything you Need to Know




Emulator Cadence 1.0 Support

The Flow Emulator now supports Cadence 1.0. This includes integration of a new Cadence 1.0 type checker and the full suite of language features. Developers can start updating their contracts, transactions, and scripts to the new version right on their local machines.

Dec 2023

Emulator EVM Support

The Flow Emulator now enables local deployment of Solidity contracts and simulation of transactions.

Jan 2024

Crescendo Previewnet Live

An early access version of the upgraded Crescendo network that supports both EVM and Cadence 1.0. This is the perfect place for developers to test their updated applications, supporting Flow Reference Wallet, Flowdiver and more. Please note that Previewnet does not support data or state migration.

Feb 2024

Cadence 1.0 Contract Staging Enabled

Release of a new staging process. This allows developers to map their updated and rewritten Cadence 1.0 code to their existing pre-Cadence 1.0 deployed code. When the upgrade occurs, your staged code will automatically replace the live contracts. Staging is available on both Testnet and Mainnet and will replace contracts on both respectively.

Mar 2024

Testnet Migration Environment Live

A specialized test environment that mimics the Testnet, including staged contracts and data migration. Please be aware that the state will be reset weekly. This environment is ideal for ensuring your updates function as expected on the network, offering a close simulation of their post-upgrade functionality.

Apr 2024

Cadence Migration Stages on Testnet

Stage 1 (May 22-23): Focus on testing applications with Transaction Inspection Logic that actively blocks 100% of failing transactions.
Stage 2 (May 29-31): Extended interaction with the environment to refine code and resolve issues.
Stage 3 (June 5-8): Deeper testing to finalize migration strategies.
Stage 4 (June 12-17): Simulate a full migration to ensure readiness for the network upgrade.

May 2024

Testnet Network Upgrade

What to expect: A full network upgrade on the Testnet will be implemented.

Goal:  Confirm that all systems and applications are fully compatible and operational post-upgrade.

Date coming soon - read announcement

Enabling EVM on Testnet

Right after the network upgrade, the EVM will be activated on the Testnet, allowing you to start deploying and testing your EVM-compatible contracts and tools in the newly updated environment. This is a pivotal moment in the Crescendo migration on the Flow blockchain, designed to streamline the transition and enable you to utilize enhanced capabilities efficiently.

Date coming soon - read announcement

Crescendo Upgrade on Flow Mainnet

All staged Cadence 1.0 contracts on Mainnet replace live contracts.  EVM will be activated several weeks later.

Date coming soon - read announcement

EVM Activated on Mainnet

All staged Cadence 1.0 contracts on Mainnet replace live contracts.  EVM will be activated several weeks later.

Date coming soon - read announcement

with the Community

Learning Communities
Emerald DAO
Flow Github


How does this affect me?

I am a developer

I deployed a smart contract on testnet and/or mainnet
I have have started working on a dapp but I haven’t yet deployed a smart contract on mainnet

I am a node operator

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I am not (yet) a developer/builder, but I am interested in building on Flow

Start learning Cadence 1.0

I am a user of a app on Flow

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