Understanding receipt serialisation on inclusion in a block.

[mfornet]

Each block contains the merkle-root of the MPT that contains all receipts. Receipts are serialised as a tuple of four values, and I want to understand how is the first value determined.

• Serialisation of the receipt
• The first value correspond with statusEncoding.

I noticed that it can be either a "boolean" (0x00 or 0x01), or instead the merkle root of the state after applying the relevant tx.

When is the boolean value used, and when is the merkle root used?

For more information about this, I opened a question in Ethereum SE, and this issue: Near-One/rainbow-bridge#557

[MariusVanDerWijden]

The merkle root was used a long time ago, now only 0 or 1 is saved in the receipt depending on whether a transaction was successful
ethereum/EIPs#98