# 4.x

## Summary

This upgrade moved cheqd to support **Cosmos SDK v0.50 "Eden"**.

**Cosmos SDK v0.50** is a long-term support version bringing major improvements in performance, developer experience, and modularity. Key features include **ABCI++** for more flexible and efficient consensus and **IAVL 1.0** for faster and more efficient data storage. It also adds **Optimistic Execution** to reduce block times and **Sign Mode Textual** for clearer, more secure transaction signing. This release sets a solid foundation for building faster, more customizable applications on cheqd.

We also **enhanced our DIDs** to support a more flexible **service section**, enabling direct connections to `did:cheqd` DIDs using **DIDComm**. This enhancement brings full cheqd support for **DIDComm endpoint discovery**, making it easier for apps and SDKs like **ACA-Py** and **Credo** to integrate seamless messaging and communication.

### Breakdown of new features

#### ⚙️ ABCI++ Integration

Introduces **programmable consensus** by extending the Application Blockchain Interface (ABCI) with new lifecycle hooks.

**Key Improvements**

* Application developers gain **greater control over block processing** and **state transitions**.
* Enables **custom consensus logic** that can be tailored to specific application needs (e.g. advanced voting, inter-block dependencies).
* Allows decoupling of consensus steps, improving both **flexibility** and **performance**.

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#### ⚡ Optimistic Execution

Introduces support for executing transactions *before* consensus is finalized.

**Key Improvements**

* **Reduces block time** and latency by speculatively executing blocks.
* Enhances the performance of **high-throughput applications**.
* Improves **UX for end-users** by speeding up transaction confirmations without sacrificing safety.

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#### 🧩 IAVL 1.0 Merkle Trees

An upgrade to the core data structure used for state storage in the Cosmos SDK.

**Key Improvements**

* **Faster reads and writes** from disk.
* Significantly improved **disk usage and storage efficiency**.
* Makes the ledger more scalable as data grows.

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#### ✍️ Sign Mode Textual

A new signing mode that enhances **human readability and security** of transactions.

**Key Improvements**

* Makes signing workflows **more understandable for humans**, especially in multisig or governance scenarios.
* Ideal for **wallet interfaces** and **offline signing** tools.
* Enhances **auditability and transparency** of what is being signed.

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#### 🔌 DIDComm Enhancement for `did:cheqd`

We’re upgrading our DIDs to support a **more flexible service section**—a key step toward making `did:cheqd` fully interoperable with DIDComm.

**Key Changes**

* Enables **direct DIDComm connections** using `did:cheqd` identifiers.
* Adds support for **DIDComm endpoint discovery** within DID Documents.
* Enhances compatibility with **identity SDKs and agents** such as ACA-Py and Credo.

These updates pave the way for seamless messaging and secure interactions between agents using cheqd DIDs.

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### 🌟 What This Means for You

* **Faster performance & better tooling**: Cosmos SDK v0.50 makes node operation and application development smoother and more efficient.
* **Stronger identity integrations**: Full DIDComm support will enable easier adoption of cheqd DIDs in SSI ecosystems.
* **Future-proofing**: This release lays the foundation for new features and upgrades in identity, governance, and interoperability across the Cosmos ecosystem.