To complete an upgrade and avoid slashing:

1. Access the upgrade section in the Sauces app.
2. Select the level you wish to upgrade to and note the required amount of ICE coins.
3. Send the exact amount of ICE coins to the specified address provided in the app.
4. Submit the transaction ID within the app within 15 minutes to confirm your upgrade.
5. Ensure the transaction is accurate to avoid any mistakes or loss of funds. Upgrading to higher levels can provide immunity from slashing penalties.