Forks — activation heights

Each fork introduces new tx types and consensus rules. Activation is by block height, configurable per environment via env vars:

Fork	Default mainnet height	Env override	Tx types activated	Section
V2	7500 (active)	OMBRA_FORK_HEIGHT	Fee split 70/25/5, PoTU burn, attestations	Tokenomics
V3	18554 (active)	OMBRA_FORK_HEIGHT_V3	ART_MINT, ART_TRANSFER, ART_BURN	NFT Mint
V4	999_999_999 (inactive)	OMBRA_FORK_HEIGHT_V4	IMAGE_MINT, IMAGE_TRANSFER, IMAGE_BURN	NFT Mint
V5	999_999_999 (inactive)	OMBRA_FORK_HEIGHT_V5	AUDIO_MINT, AUDIO_TRANSFER, AUDIO_BURN	NFT Mint
V6	999_999_999 (inactive)	OMBRA_FORK_HEIGHT_V6	CHAT_TURN, AGENT_REQUEST/CLAIM/STEP/FINISH	Chat + Agent

Inactive forks have height 999_999_999 so the chain rejects post-fork tx types on mainnet. Operators activate by setting an env override.

Check current activation

curl https://api.ombra-net.com/api/chain/stats

Response includes height. Compare against the table above.

Behavior at activation

When block height crosses a fork threshold:

1. New tx types become valid in mempool
2. Older nodes (unaware of the fork) reject these txs → they get partitioned off
3. State storage adds new record types for the fork
4. SDK clients should refuse to construct fork tx if chainHeight < forkHeight (defensive)

Example check in TS:

const { height } = await client.chain.getStats();
const FORK_V6 = 65500;  // current mainnet activation
if (height < FORK_V6) throw new Error("Fork V6 not yet active");

Why env overrides

Local testnet and CI deployments need to enable forks instantly. The OMBRA_FORK_HEIGHT_* env vars let operators set =1 for immediate activation at genesis. Mainnet operators coordinate a real height via social consensus, then publish the env value to all node runners.

Coordination

Activating a fork on mainnet requires:

1. Software supports the fork (deployed node version)
2. A majority of validators run that version
3. All validators set the same OMBRA_FORK_HEIGHT_X=N value
4. Once block N is produced, fork is locked in

Operators that miss the coordination get partitioned and stop validating.