Our Products
Oct 27, 2025
6
minutes read
Unpacking Major Improvements for Smart Contract Development in Tycho
Threaded Solidity (T-Sol) the smart contract language in the Tycho blockchain protocol, while Locklift serves as the core tool for building, testing, and managing contracts there. In the recent months, Broxus developers introduced a series of major updates to both T-Sol and Locklift to bring new capabilities and address important compatibility challenges. In this article, we’ll take you behind the scenes of the technical challenges engineers faced, the solutions they implemented, and the new capabilities these solutions brought for smart contract development in Tycho.
Overcoming Biggest Challenges
Enhancements began with updates to the TVM Solidity Compiler. Version 0.72.0 introduced the “sold” utility, its new core component for building contracts, replacing the previous “solc” and “tvm_linker” toolset. Shortly after, version 0.73.0 brought a new ABI (Application Binary Interface) v2.4, which contained numerous breaking changes.
These breaking changes created a critical challenge, as they were not supported by Locklift and Broxus SDK. This effectively prevented the developer community from using any compiler version newer than 0.72.0, blocking access to subsequent features and improvements.
To resolve this challenge, Broxus found itself at a crossroads with several potential paths:
Maintain an alternative branch based on the older, pre-change compiler version.
Migrate to tooling from the related TON blockchain protocol.
Embrace the challenge and integrate full support for these breaking changes.
Eventually, engineers chose a strategic combination of the second and third options: they committed to supporting ABI v2.4 while also building a bridge to a parallel ecosystem. This strategy involved leveraging Tycho, a high-performance, DAG-based blockchain protocol also derived from the original TON design. To achieve this, they developed a TON Center Compatible API for Tycho and Tycho Emulator (Tycho executor for TON Sandbox), enabling the use of TON-native tools within the protocol. This dual approach allowed for further improvement of Threaded Solidity without limiting the choice of developer tools.
What’s New in Locklift
The updated Locklift is packed with powerful features designed to make building and testing smart contracts in T-Sol more efficient and intuitive:
Full support for the latest Compiler’s versions. Locklift is now fully compatible with TVM Solidity Compiler versions 0.72.0 and higher, utilizing the “sold” utility for modern contract builds.
Integration with Tycho. Locklift now uses the Tycho Virtual Machine (Tycho VM) for local testing. This provides an environment that mirrors the Tycho protocol, giving developers early access to features enabled at its core.
Enhanced debugging. Debugging is now easier with full support for tvm.log, allowing you to print detailed information directly from your smart contract during execution.
Network forking. A game-changing feature for testing: it is now possible to create a local snapshot of any set of smart contracts and their states. This allows for testing complex interactions in a realistic, isolated environment without any real-world consequences.
Arbitrary state management. For ultimate testing flexibility, developers can now set any state for any address. This empowers them to simulate edge cases and complex scenarios that would be difficult or impossible to set up on a live network.
T-Sol Advancements
Alongside Locklift, Threaded Solidity itself has also received significant upgrades.
First, a new “unpacked” keyword was featured. It gives developers granular control over the lifecycle of variables unpacked from persistent contract storage (register C4) into temporary memory (register C7). For contracts with many state variables where some are used infrequently, this can lead to significant gas savings.
Next, the language received the possibility of creating and using libraries, immutable cells of code or data deployed to the masterchain. For instance, the decimals and name for a TIP-3 (fungible token standard) collection can be stored in a data library, allowing any contract to load this data on-demand by referencing the library's hash.
One more change added additional warning in case an action is generated after an action with flag 128 (a finalizing flag, often used to send the entire remaining balance). This helps prevent logical errors where further actions might be unintentionally discarded.
Finally, T-Sol now includes explicit external message handling. To create cleaner and more predictable code, the runtime for processing external messages is no longer generated by default. Instead, you must now explicitly use the “ExternalMessage” attribute to enable it in your contract.
These advancements in Locklift and T-Sol are a direct result of our commitment to providing the best possible tools for the Tycho developer community. Overall, these new capabilities promise to unlock new possibilities and streamline the development of next-generation decentralized applications.
