Many changes have occurred in both the Kava software and the cosmos-sdk software since the launch of kava-2. The primary changes in Kava are the addition of modules that comprise the [CDP system](https://docs.kava.io/). To review cosmos-sdk changes, see the [changelog](https://github.com/cosmos/cosmos-sdk/blob/v0.38.4/CHANGELOG.md) and note that kava-3 is launching with __v0.38.4__ of the cosmos-sdk.
### Risks
As a validator, performing the upgrade procedure on your consensus nodes carries a heightened risk of double-signing and being slashed. The most important piece of this procedure is verifying your software version and genesis file hash before starting your validator and signing.
The riskiest thing a validator can do is discover that they made a mistake and repeat the upgrade procedure again during the network startup. If you discover a mistake in the process, the best thing to do is wait for the network to start before correcting it. If the network is halted and you have started with a different genesis file than the expected one, seek advice from a Kava developer before resetting your validator.
### Recovery
Prior to exporting kava-2 state, validators are encouraged to take a full data snapshot at the export height before proceeding. Snapshotting depends heavily on infrastructure, but generally this can be done by backing up the .kvd and .kvcli directories.
It is critically important to back-up the .kvd/data/priv_validator_state.json file after stopping your kvd process. This file is updated every block as your validator participates in consensus rounds. It is a critical file needed to prevent double-signing, in case the upgrade fails and the previous chain needs to be restarted.
In the event that the upgrade does not succeed, validators and operators must downgrade back to v0.3.5 of the Kava software and restore to their latest snapshot before restarting their nodes.
Set your node to produce the final block of kava-2 at __13:00__ UTC June 10th, 2020. To restart your node with that stop time,
```
kvd start --halt-height 1591794000
```
Kava developers will update this PR with the final block number when it is reached. __Make sure the kvd process is stopped before proceeding and that you have backed up your validator__. Failure to backup your validator could make it impossible to restart your node if the upgrade fails.
