Juno v19 — Rhea

Junø ⚵
3 min readJan 29, 2024

Rhea, the first Juno software upgrade of 2024, is coming to the mainnet! Packed with exciting features, this upgrade is a game-changer for Juno’s future. Get ready for a smoother and more powerful experience as Juno takes a leap forward, bringing new tools and connecting to the Polkadot-Kusama ecosystem.

Major Changes

Notable changes

x/Clock Module is now permissionless

The Clock Module is a feature that was firstly introduced by Juno in the v17 — Vesta upgrade. With x/Clock Module, developers can register their contracts to ‘tick’ (be called upon) every single block with a significant amount of computation. This enables teams to cease running additional infrastructure and instead utilize the chain functions for their contracts. However, developers previously required governance permission to register their contracts for per-block execution. With the latest upgrade, the x/Clock Module will now be entirely permissionless and available for everyone to use!

Wasm Light Client (Polkadot)

A significant milestone in Rhea is Juno establishing IBC connection with the Polkadot ecosystem. By adding the WasmClient, Juno will be able to interact with Polkadot Parachains like Composable finance via IBC. This deployment (developed by the Strangelove team) signifies a pivotal development. Not only does it mark the opening of pathways to numerous possibilities but also lays the foundation for potential partnerships and alliances with various Polkadot communities and projects. With this upgrade, Juno leads the way as the first Cosmos chain to establish a connection with the Polkadot ecosystem, other than Composable Finance which Juno can connect through, or other Parachains that adopt the Wasm Client in the future.

Please be aware that the Juno<>Polkadot connection will not be instantly active, as there is an anticipated parachain update from Composable’s side, too.

Migrate Core-1 Multisig to Charter Council

With Rhea, the transfer of vesting and payroll contracts from Core-1 will be successfully concluded. Following the dissolution of the Core-1 SubDAO, the upgrade is designed to accomplish a dual purpose: to facilitate the transfer of funds from the Core-1 legacy multisig to the council, and notably to transform the Core-1 vesting account into a standard baseAccount. This will imply the availability of vesting cancellations and transforming other vesting accounts, a crucial step to ensure the smooth execution of the next upgrade, during which all previously vested funds of Core-1 will be transferred without any unforeseen issues.

Enforce Validator’s Max 24 Hour Commission Change Rate To 5%

This significant update is designed to safeguard the community against the potential abrupt increase in a validator’s commission overnight. An incident of this nature has already occurred in the active set of Cosmos Hub, where a validator suddenly changed its commission to 99.35% and earned profits to the detriment of its delegators. The implemented change aims to address such occurrences and protect the stability of the network.

Notable changes for developers & validators

Updated to wasmvm 1.5.2

Juno will maintain its cutting edge tech stack by upgrading to them newest version of wasmvm. Wasmvm 1.5.2 addresses an issue with growing memory usage over time introduced in 1.4.

Wasm memory leaks fixes

After the Juno v18 — Epona upgrade, certain validators experienced memory leak issues. Despite the identification of workarounds, the latest upgrade will successfully address and resolve these concerns, ensuring smooth functionality.

Closing Thoughts

Rhea will be one significant milestone in Juno’s journey as it will open a portal to an amazing ecosystem like Polkadot, unlocking countless possibilities and bringing communities together.

Even more important, it will be the first on-chain initiative to dissolve Core-1. The takeover from the Charter’s Council means the Juno ecosystem is officially stepping into a new era. Now, a group elected by Juno stakers is responsible for guiding and assisting the community and leading the ecosystem towards a better future!

Juno is a fully transparent and decentralized smart contract blockchain bringing true power to the community. Learn more and actively contribute to Juno by connecting with our official accounts.

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