{"document_id":"BLC-STUDY-0419","slug":"erc-4906","title":"EIP-721 Metadata Update Extension","authors":"Anders , Lance , Shrug , Nathan","year":2022,"date_label":"2022","publisher":"Anders , Lance , Shrug , Nathan","paper_type":"Design paper","category":"Privacy","topics":["Privacy"],"source_url":"https://eips.ethereum.org/EIPS/eip-4906","source_label":"ERC 4906","legacy_pdf_path":null,"sha256":null,"sha256_note":"No hash is published. This build does not store those PDF bytes, so a checksum would be invented. Where a legacy path exists, it points at the Internet Archive copy of the old library.","version":"Source cited by the 2022 study. The study is the reading. This page does not add a second essay.","doi":null,"rights_status":"Official external source only","source_status":"Official source","use_status":"Metadata and commentary only. The reading is the study page.","licence":null,"licence_label":"No licence recorded. Rights status under review.","full_text":null,"full_text_reason":"Full text is not published on this page. Public availability is not a licence to republish a document. Blockchain Lab has not recorded a licence that permits an HTML transcription, a training set, or a retrieval corpus of the paper. Text on this page is Blockchain Lab's own wording, or a pointer to a study that is also Blockchain Lab's wording.","editorial_line":"ERC 4906, EIP-721 Metadata Update Extension. Many EIP-721 contracts emit an event when one of its tokens' metadata are changed.","canonical_url":"https://blockchainlab.com/whitepaper/erc-4906","record_url":"https://blockchainlab.com/research/corpus/papers/erc-4906","study_url":"https://blockchainlab.com/whitepaper/erc-4906","last_reviewed":"2026-10-01","last_checked":"2026-10-01","relationships":[{"rel":"Canonical reading","label":"ERC 4906 study","href":"/whitepaper/erc-4906"},{"rel":"Related paper","label":"Groth16","href":"/whitepaper/groth16"},{"rel":"Related paper","label":"Bulletproofs","href":"/whitepaper/bulletproofs"},{"rel":"Related paper","label":"Taproot","href":"/whitepaper/taproot"}]}