UIDs versus sequence numbers
02Sequence numbers track current positions; UIDs support persistent synchronization.
Terms in this drawing
Related RFCs and changes
“Updates” changes part of an earlier RFC. “Obsoletes” replaces it. This list shows selected related documents.
DIAGRAM§ 2.3.1 ↗
RFC 9051 · § 2.3.1EXAMPLE
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03
Keep UID identity
UIDs for the surviving messages remain associated with their original identities.
Protocol participantThreat or exceptionProtocol controlSimplified drawings · precise section references
Read the updated RFC section ↗
A UID is a nonzero 32-bit value that increases within a mailbox.
- A UID is a nonzero 32-bit value that increases within a mailbox.
- UIDVALIDITY is needed to interpret persisted UID state.
- Sequence numbers can change when messages are expunged.
Examples are illustrative. Consult the linked RFC and its errata for implementation details.
Read the RFC section ↗Diagrams simplify the RFC. Read the linked sections for complete requirements.
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