**Table of Contents** *generated with [DocToc](https://github.com/thlorenz/doctoc)* - [The Merge -- Client Settings](#the-merge----client-settings) - [Override terminal total difficulty](#override-terminal-total-difficulty) - [Override terminal block hash](#override-terminal-block-hash) # The Merge -- Client Settings **Notice**: This document is a work-in-progress for researchers and implementers. This document specifies configurable settings that clients must implement for the Merge. ### Override terminal total difficulty To coordinate manual overrides to [`TERMINAL_TOTAL_DIFFICULTY`](./beacon-chain.md#Transition-settings) parameter, clients must provide `--terminal-total-difficulty-override` as a configurable setting. The value provided by this setting must take precedence over pre-configured `TERMINAL_TOTAL_DIFFICULTY` parameter. Clients should accept the setting as a decimal value (i.e., *not* hexadecimal). Except under exceptional scenarios, this setting is not expected to be used. Sufficient warning to the user about this exceptional configurable setting should be provided. ### Override terminal block hash To allow for transition coordination around a specific PoW block, clients must also provide `--terminal-block-hash-override` and `--terminal-block-hash-epoch-override` as configurable settings. * The value provided by `--terminal-block-hash-override` takes precedence over the pre-configured `TERMINAL_BLOCK_HASH` parameter. * The value provided by `--terminal-block-hash-epoch-override` takes precedence over the pre-configured `TERMINAL_BLOCK_HASH_ACTIVATION_EPOCH` parameter. Except under exceptional scenarios, these settings are not expected to be used. Sufficient warning to the user about this exceptional configurable setting should be provided.