Terra Classic Has One Day Left Before Mandatory v4.0.1 Patch Upgrade
Terra Classic is now one day away from a mandatory network upgrade that will address a critical security vulnerability affecting key smart contract components. The coordinated upgrade to v4.0.1-patch.3 is scheduled to activate at block height 30,544,730, with the halt currently estimated for Thursday, September 24, 2026, at 15:00 UTC.
The exact timing may vary as block production changes. Terra Classic node operators are therefore advised to monitor the network block height rather than relying only on the estimated clock time.
The upgrade applies to the columbus-5 network and is being coordinated through an on chain software upgrade named v14_3. According to the official Terra Classic release, the update is mandatory for nodes that need to remain connected to the network.
Terra Classic Upgrade Scheduled for September 24
The Terra Classic network will automatically halt at block 30,544,730 to activate the v14_3 software upgrade.
| Upgrade Detail | Information |
|---|---|
| Network | Terra Classic columbus-5 |
| Upgrade | v4.0.1-patch.3 |
| Upgrade Plan | v14_3 |
| Upgrade Block | 30,544,730 |
| Estimated Date | September 24, 2026 |
| Estimated Time | 15:00 UTC |
| Vulnerability Disclosure | September 28, 2026 at 14:00 UTC |
| Purpose | Security fix for wasmd and wasmvm |
| State Migration | None |
| New Store | None |
| Parameter Change | None |
The estimated timing is based on recent block production, meaning the actual halt can occur earlier or later. The official release advises operators to track the current block height instead of depending only on the estimated time.
Critical Security Vulnerability Behind the Upgrade
The primary reason for the mandatory Terra Classic upgrade is security.
The wasmd and wasmvm components used by Terra Classic’s smart contract platform are affected by a critical security vulnerability. The issue is being handled through responsible disclosure, with the full details of the vulnerability scheduled to be publicly disclosed on September 28, 2026, at 14:00 UTC.
Terra Classic core maintainers have already incorporated the required fix into terrad and released it as v4.0.1-patch.3.
The timing of the upgrade is important because the network needs to be running the patched software before the vulnerability details become public.
Until the public disclosure, details of the vulnerability and the fix are being handled through private channels.
No State Migration or Parameter Changes
The upcoming upgrade is focused on the security fix and does not introduce a state migration.
According to the official release, there is no migration, no new store and no parameter change.
The release instead updates the software and consensus behavior required to keep Terra Classic operating with the security fix in place.
This means the upgrade is primarily a software and security update rather than a change to Terra Classic’s existing network parameters or blockchain state.
Why Terra Classic Is Using an On Chain Upgrade
The upgrade changes consensus behavior, meaning validators and node operators need to transition to the new software at the same predetermined block height.
Rather than relying on operators to coordinate an off chain halt independently, Terra Classic is using an on chain software upgrade mechanism.
This allows the network to coordinate the halt at block 30,544,730.
Once the upgrade height is reached, nodes running the existing software will stop and will not be able to continue producing or syncing blocks until they are upgraded.
The coordinated approach is particularly important because Terra Classic has a large validator and infrastructure ecosystem. An on chain upgrade provides a common trigger that allows participating nodes to transition at the same network height.
Who Needs to Upgrade?
The requirement applies broadly to infrastructure running the Terra Classic columbus-5 network.
| Infrastructure | Upgrade Required |
|---|---|
| Terra Classic Validators | Yes |
| RPC and LCD Providers | Yes |
| Exchanges | Yes |
| IBC Relayers | Yes |
| Blockchain Explorers | Yes |
| Bridges | Yes |
| Wallet Infrastructure | Yes |
| VaaS Providers | Provider dependent |
In general, any operator running a columbus-5 node needs to ensure that the node is prepared for the scheduled upgrade.
Nodes that have not upgraded will stop at block 30,544,730 and will not continue with the upgraded network.
Validator as a Service Providers
Operators using a Validator as a Service provider or white label infrastructure provider may not need to perform the upgrade themselves.
The infrastructure provider may handle the binary update on behalf of the validator.
Operators who are unsure should contact their provider before the upgrade height and confirm that their node will be updated to v4.0.1-patch.3.
Terra Classic Operators Should Prepare Before the Halt
The official release provides binaries for both Linux x86_64 and Linux ARM64 systems.
The available files and checksums include:
| Release File | SHA256 Checksum |
|---|---|
terra_4.0.1-patch.3_Linux_x86_64.tar.gz |
4b1428ace2f9c328a813ea0739104c3f506095d3849acdfc5e673fe2d22fd7b3 |
terra_4.0.1-patch.3_Linux_arm64.tar.gz |
94cc1189902c4bc0c5b570c0c2cfedc90041ffeed510aa9e126e13953f0d93bf |
checksums.txt |
Checksum verification file |
Operators should download the software only from the official Terra Classic release and verify the checksum before installing it.
Operators running ARM machines should use the ARM64 binary rather than the x86_64 version.
What Operators Need to Know Before the Upgrade
Operators should prepare the v4.0.1-patch.3 release before the scheduled upgrade but should not replace the existing binary before the network reaches the designated upgrade height.
At block 30,544,730, nodes running the current software are expected to halt for the coordinated upgrade.
After the halt, operators need to follow the official release instructions to switch to the patched v4.0.1-patch.3 binary and restart their nodes.
The official release notes contain the complete upgrade instructions and should be followed carefully to avoid interrupting node operations unnecessarily.
Do Not Use Unsafe Skip Upgrades
Operators should not use --unsafe-skip-upgrades to bypass the scheduled upgrade.
Skipping the upgrade would leave the node on the vulnerable software and prevent it from following the coordinated network upgrade.
The purpose of the mandatory upgrade is to ensure that Terra Classic infrastructure is running the patched software before the vulnerability details are publicly disclosed.
What Happens at Block 30,544,730?
At the scheduled upgrade height, Terra Classic nodes running the existing software will halt.
The network will then transition to v4.0.1-patch.3 as validators and infrastructure operators restart their upgraded nodes.
Block production is expected to resume once validators representing more than two thirds of voting power are running the new release.
Validators that have not upgraded will miss blocks while their nodes remain offline. They may also face downtime related consequences under the network’s existing rules.
No state rollback or blockchain export is required for this upgrade.
What Terra Classic Users Need to Know
For ordinary $LUNC holders, the upgrade does not require a token migration or a change to the existing blockchain state.
The main responsibility falls on infrastructure operators running Terra Classic nodes and services.
Users interacting with exchanges, wallets or other services may not need to take any direct action, but service providers need to ensure their infrastructure is upgraded and ready for the network halt.
Terra Classic Upgrade Deadline Is Approaching
Terra Classic now has approximately one day before the scheduled v4.0.1-patch.3 upgrade.
The most important number for node operators to monitor is block 30,544,730. The estimated September 24 time is only an approximation because actual block production can vary.
The upgrade is being implemented ahead of the planned September 28 vulnerability disclosure, giving Terra Classic infrastructure operators time to move to the patched software before the security issue becomes public.
The upgrade does not introduce a new token, state migration or parameter change. Its primary purpose is to deploy the security fix and ensure Terra Classic nodes continue operating on the coordinated upgraded network.
