Avalanche's v1.15.2 removes Coreth and retires several deprecated C-Chain options
Victoria Shinder1 min readAvalancheGo v1.15.2, named Helicon.2, removes Coreth, the legacy C-Chain client, completing a transition the network began with the Helicon upgrade. That creates one path dependency operators have to respect: a node whose last run predates the Helicon activation cannot jump straight to this version. It has to come up on v1.15.0 or v1.15.1 for long enough that its C-Chain crosses the Helicon point, or else drop its database and resync from scratch. The release also adds a consolidated EVM client under vms/evm/evmclient that bundles the ordinary Ethereum calls, the Geth extensions, low-level RPC access and Avalanche's own EVM methods in one place.
A round of cleanup accompanies the removal. Items deprecated back in v1.15.0 are gone: the avax.getAtomicTxStatus RPC, replaced by avax.getAtomicTx; the eth-apis option, now ignored with a warning in favour of apis; and a P-Chain gossip config key that had been inert since v1.14.2. C-Chain metrics drop their transition prefix, so dashboards that match on metric names will need updating, and new gauges expose unsettled gas and the headroom in the execution-gas rate.
What it means
Retiring Coreth is the headline because it ends a dual-client era for Avalanche's C-Chain, and running two implementations of the same chain is exactly where quiet consensus-divergence bugs hide. For operators, though, the load-bearing sentence is the upgrade path, not the removal: it is the detail that turns a routine bump into a node that will not sync, because an old node skipping the intermediate release cannot carry its C-Chain across the Helicon boundary. The rest — pulling options deprecated two or three releases ago, deleting a config key that has done nothing for a year — is a project keeping its own house honest. Read the upgrade note before touching any long-idle node; everything else here is housekeeping.