> For the complete documentation index, see [llms.txt](https://vinu.gitbook.io/vinuchain/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://vinu.gitbook.io/vinuchain/technical-docs/vinuchain-mainnet/elemont-upgrade.md). # ELEMONT Upgrade The **ELEMONT** upgrade is VinuChain mainnet's hard-fork to the modern EVM and the V2 staking contract. It is **live on testnet (chain ID `206`)** and is **scheduled for mainnet (chain ID `207`) on 29 August 2026 at 10:00 UTC**. This page is the single reference for what ELEMONT changes, the new RPC surface it exposes, and what node operators need to know. {% hint style="warning" %} **Mainnet has not activated ELEMONT yet.** Until the 29 August activation seals, mainnet runs the pre-ELEMONT rule set — `Berlin`, `London`, `Llr`, `Podgorica` — and the **V1** SFC staking contract. Everything on this page described as an ELEMONT feature is live on testnet today and arrives on mainnet at that activation. Node operators: the step-by-step procedure is in the [Mainnet Upgrade Guide (ELEMONT)](/vinuchain/technical-docs/vinuchain-mainnet/chain-upgrade-guide.md). Two pre-flight items (transaction indexing and the Go toolchain) need lead time — start now. {% endhint %} > **TL;DR** — The 2026-08-29 release brings mainnet to **full parity with testnet**: SfcV2 (V2 staking + 30% base-fee burn), the Shanghai / Cancun / Prague EVM (including EIP-7702 set-code transactions), the Elemont consensus fixes, canonical-pubkey validation, the BLS12-381 and latest-EVM precompiles, and PaybackV2 (a new fee-refund contract) — on top of the already-live Llr and Podgorica features. The new binary also exposes a branded `vc_*` JSON-RPC namespace, `vc_getPaybackBalance`, and `eth_config`. **Fee-refund stakers must migrate to the new Payback contract** — see the [Mainnet Upgrade Guide](/vinuchain/technical-docs/vinuchain-mainnet/chain-upgrade-guide.md#if-you-stake-in-the-payback-fee-refund-contract). Activation crosses five consecutive epoch seals over roughly 17 hours. ## Check what mainnet is running right now Do not take this page's word for it — ask the chain: ```bash curl -s -X POST https://rpc.vinuchain.org \ -H 'Content-Type: application/json' \ -d '{"jsonrpc":"2.0","method":"vc_getRules","params":["latest"],"id":1}' \ | python3 -m json.tool ``` * **Before the activation:** `Upgrades` contains exactly `Berlin`, `London`, `Llr`, `Podgorica`. * **After the activation:** it additionally reports `Shanghai`, `Cancun`, `Prague`, `SfcV2`, `Elemont`, `ElemontPubkeyValidation`, `VinuBLS12381`, `VinuLatestEVM`, and `PaybackV2` — and `Economy.QuotaCacheAddress` **changes** from the V1 proxy `0x1c4269fbbd4a8254f69383eef6af720bcd0acda6` to the new `QuotaContractV2`. The flags arrive across five consecutive epoch seals, not all at once. The SFC staking contract's own version is the clearest single signal: ```bash curl -s -X POST https://rpc.vinuchain.org -H 'Content-Type: application/json' \ -d '{"jsonrpc":"2.0","method":"eth_call","params":[{"to":"0xFC00FACE00000000000000000000000000000000","data":"0x54fd4d50"},"latest"],"id":1}' # 0x3330340... = "304" = SFC V1 (pre-ELEMONT) # 0x3330350... = "305" = SFC V2 (post-ELEMONT) ``` ## What ELEMONT activates on mainnet | Feature | What it means | | --------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ | | **SfcV2** | V2 SFC (staking) bytecode at `0xFC00FACE…0000`, with a **30% burn of the validator base-fee share**. | | **Shanghai** | `PUSH0`, warm coinbase, and Shanghai transaction rules. | | **Cancun** | Selected (non-blob) Cancun: transient storage (`TLOAD`/`TSTORE`), `MCOPY`, and the Cancun `SELFDESTRUCT` (EIP-6780) semantics. Blob transactions (EIP-4844) and the `BLOBBASEFEE` opcode (EIP-7516) are **not** enabled. | | **Prague** | **EIP-7702 set-code transactions** (type `0x04`) — EOAs can delegate to contract code, the foundation for account-abstraction UX on ordinary wallets. | | **Elemont** | Consensus-critical correctness fixes (merged no-cheaters view, full ABI decode of epoch advances, cheater-fee zeroing, deterministic vector-clock tie-breaking, stable median-time sort, empty-pubkey validator skip at epoch seal). | | **ElemontPubkeyValidation** | Validator pubkeys must be the canonical 66-byte `0xc0`-prefixed Secp256k1 form at every on-chain ingress (`createValidator`, `_rawCreateValidator`, `updateValidatorPubkey`). Malformed keys are rejected. | | **VinuBLS12381** | The EIP-2537 BLS12-381 precompile family at `0x0b`–`0x11`. | | **VinuLatestEVM** | `P256VERIFY` at `0x0100`, `CLZ`, MODEXP bounds/repricing, and the EIP-7825 per-transaction gas cap. | | **PaybackV2** | Payback / fee-refund moves off the V1 Quota proxy onto a newly deployed non-proxy `QuotaContractV2`. **Fee-refund stakers must migrate.** | Berlin, London (EIP-1559 base fee), **Llr**, and **Podgorica** (the Payback / fee-refund system) are already active on mainnet today and remain so. ## New RPC surface ELEMONT ships a richer RPC surface. It is live on the testnet endpoint `https://vinufoundation-rpc.com` today, and arrives on the public mainnet endpoint `https://rpc.vinuchain.org` with the 29 August activation. Of these, only `vc_getRules` is available on mainnet's current binary. | Method | Purpose | On mainnet today? | | ----------------------------------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | --------------------------- | | `vc_*` namespace | The full `eth_*` JSON-RPC surface mirrored under a branded `vc_` namespace — e.g. `vc_blockNumber`, `vc_call`, `vc_getBalance`, `vc_getTransactionReceipt`, `vc_sendRawTransaction`, `vc_getRules`. (Filter/subscription methods such as `eth_getLogs` / `eth_subscribe` remain under `eth` only.) | Partial — `vc_getRules` yes | | `vc_getRules(blockTag)` | Active network rules for the epoch, including every upgrade flag and `Economy.QuotaCacheAddress`. | **Yes** | | `vc_getPaybackBalance(address, blockTag)` | The wallet's currently available Payback quota in wei (its fee-refund cap for the next transaction). Process rate-limited; overload returns error `-32005`. | No — arrives with ELEMONT | | `eth_config` / `vc_config` | Returns the current / next / last fork configuration — `chainId`, `forkId`, the per-fork `activationBlock` (VinuChain forks at block height), and the precompile map. | No — arrives with ELEMONT | See [Public API Endpoints](/vinuchain/technical-docs/api/public-api-endpoints.md) for the full endpoint list. ## What this means for you ### dApp developers * **Modern EVM — after the activation.** Solidity targeting the `shanghai`, `cancun`, or `prague` EVM versions compiles and runs on mainnet once ELEMONT seals; `PUSH0`, transient storage, and EIP-7702 all become available. **Do not deploy Shanghai-or-later bytecode to mainnet before then** — mainnet is a London-era EVM until the seal. See [Deploy a Smart Contract](/vinuchain/technical-docs/smart-contracts/deploy-a-smart-contract.md). * **Account abstraction.** ERC-4337 is live on testnet at the canonical cross-chain addresses. See [Account Abstraction (ERC-4337)](/vinuchain/technical-docs/smart-contracts/account-abstraction.md) for current per-network availability. * **Feeless transactions.** Already live on mainnet via Podgorica: stake into the Payback/Quota contract and eligible transactions get their gas refunded on-chain. ELEMONT does not change this, and mainnet keeps using the V1 Quota proxy `0x1c4269fbbd4a8254f69383eef6af720bcd0acda6`. See [Feeless Transactions for Developers](/vinuchain/technical-docs/smart-contracts/feeless-transactions.md). ### Stakers & validators * After the activation, the V2 SFC governs staking, delegation, lockups, and rewards, and 30% of the validator base-fee share is burned. If you integrate against the SFC ABI directly, re-check your bindings against V2. * From the activation onward, new validators must register a canonical 66-byte `0xc0`-prefixed pubkey; malformed keys are rejected at `createValidator`. See [Become a Validator](/vinuchain/technical-docs/nodes-and-validators/become-a-validator.md). * Fee-refund eligibility is driven by Payback staking — see [Staking → Overview](/vinuchain/technical-docs/staking/overview.md). ### Wallet users No action is required. Existing VC balances, addresses, and the chain ID (`207`) are unchanged by ELEMONT. ## Node operators **Mainnet operators: follow the** [**Mainnet Upgrade Guide (ELEMONT)**](/vinuchain/technical-docs/vinuchain-mainnet/chain-upgrade-guide.md)**.** It covers the pre-flight checks, the swap procedure, activation timing, the verification checklist, and rollback. The summary: The mainnet ELEMONT release is **`v2.0.49-elemont`** — the final one-install binary for 2026-08-29, superseding v2.0.48 with no EVM, state-transition, receipt-encoding, chain-rule, activation-height, or protocol-capability changes. Build it from source at commit `8b88cc49d11e56635385413fe8f9eaec1969c1ac`: **Prebuilt binary** (linux/amd64) is attached to the [`v2.0.49-elemont` release](https://github.com/VinuChain/VinuChain/releases/tag/v2.0.49-elemont): ```bash curl -LO https://github.com/VinuChain/VinuChain/releases/download/v2.0.49-elemont/opera-v2.0.49-elemont-linux-amd64 sha256sum -c <<< "678040e9f88a98331a8cc32b7bf5b9e0ae4acdf84919390465eeee584b7f56c1 opera-v2.0.49-elemont-linux-amd64" chmod +x opera-v2.0.49-elemont-linux-amd64 ./opera-v2.0.49-elemont-linux-amd64 version # Version: 2.0.49-elemont ``` It requires **GLIBC\_2.34** or newer, so it runs on Ubuntu 22.04 and later. **Or build from source:** ```bash git clone https://github.com/VinuChain/VinuChain.git cd VinuChain git checkout v2.0.49-elemont test "$(git rev-parse HEAD)" = 8b88cc49d11e56635385413fe8f9eaec1969c1ac make opera # -> build/opera ``` Requirements: **Go 1.25.13+**, a C compiler, git, and ≥ 50 GB free disk. The build pins `go-vinu v1.20.26-quota` and `lachesis-base v0.1.6-elemont` via `go.mod`. Note that mainnet's current binary was built with Go 1.19 — the toolchain upgrade is part of this work. **Upgrading an existing node** is an in-place binary swap — stop the node with a clean `SIGINT` (never `SIGKILL`, which corrupts LevelDB), replace the `opera` binary, and restart. The node continues from its existing datadir. Activation then fires at the **first epoch seal** after the validator set is on the new binary — mainnet epochs seal at most every 4 hours. **Fresh installs** should restore from a post-activation chaindata snapshot rather than replaying from the original genesis. Replaying a pre-activation genesis under the post-ELEMONT binary re-stages the fork activations at the wrong epoch seal and diverges with `wrong event epoch hash`. See [Read-Only Node](/vinuchain/technical-docs/nodes-and-validators/read-only-node.md) and the [Mainnet Upgrade Guide](/vinuchain/technical-docs/vinuchain-mainnet/chain-upgrade-guide.md). > **TxIndex must stay enabled.** ELEMONT's PaybackCache restart warm-up replays recently-sealed blocks into the in-memory Payback cache on boot to keep fee-refund accounting deterministic across restarts. A node started with transaction indexing disabled **refuses to start** (fail-closed) rather than risk divergence; if a node previously ran without TxIndex it must be re-synced (from a snapshot) with indexing on. Check this **before** upgrade day — there is no in-place fix. Verify a node is on ELEMONT after it syncs: ```bash # Client version should report v2.0.49-elemont curl -s -X POST http://localhost:18545 -H 'Content-Type: application/json' \ -d '{"jsonrpc":"2.0","method":"web3_clientVersion","params":[],"id":1}' ``` ## Also running on testnet VinuChain testnet (chain ID `206`) has been running this entire feature set for months, and the 29 August release brings mainnet to parity with it. After the activation the two networks carry the same capabilities. The only flags testnet has that mainnet will **not** set are repair mechanisms, not features: * **`SfcV2Patch1`–`SfcV2Patch10`** — re-flash flags that brought testnet's SFC bytecode up to date after its early SfcV2 activation. Mainnet's first SfcV2 activation installs the latest corrected bytecode directly. This is verifiable rather than assumed: the bytecode a fresh activation installs is byte-identical to what testnet reached after all ten patches (48,757 bytes, sha256 `134a508b13d46647052b64f8d6691f0b939d2afaa0fa400882c6653a40a77887`). * **`PaybackV2Patch`** — re-runs the PaybackV2 address rebinding for a chain that crossed that edge with a wrong address. Mainnet crosses it once, correctly. So mainnet reaches **identical on-chain state** to testnet in one step rather than replaying testnet's correction history. ## See also * [Mainnet Upgrade Guide (ELEMONT)](/vinuchain/technical-docs/vinuchain-mainnet/chain-upgrade-guide.md) — the operator procedure for 29 August * [Network Details](/vinuchain/technical-docs/network-details.md) — chain IDs, RPC/WS, explorers, key contracts * [Public API Endpoints](/vinuchain/technical-docs/api/public-api-endpoints.md) — full RPC reference incl. the `vc_*` surface * [Connect to Mainnet](/vinuchain/technical-docs/vinuchain-mainnet/connect-to-mainnet.md) — wallet quick-add * [Master Contracts Reference](/vinuchain/technical-docs/smart-contracts/contracts-master-list.md)