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mpLow

mpLow = 3

Example​

procedure ConfigureLowPriorityMessage(Message: TIdMessage);
begin
  Message.Priority := mpLow;
end;

Usage​

mpLow selects Velox's low mail-priority hint, generating non-urgent/low text headers and numeric X-Priority 4.

Additional Technical Info​

mpLow is the first below-normal TIdMessagePriority member. Generation emits Priority: non-urgent, X-Priority: 4 and Importance: low.

The example is source-reviewed and is not executed by the documentation workflow.

Behavior and boundaries

  • mpLow differs from mpLowest only in numeric X-Priority (4 versus 5).
  • It is an advisory presentation hint, not a request for delayed SMTP delivery, reduced Velox resources or altered retries.
  • It does not change IMAP flags, message ordering or business-processing priority.
  • Gateways and clients can ignore or normalize these partly nonstandard fields.

Input and round trips

Numeric first token 4 preserves mpLow. Text containing non-urgent or low maps to mpLowest. If numeric X-Priority is stripped but a textual low header remains, a load/save round trip can change level 4 to 5.

Generated values overwrite matching raw headers copied before generation; later ExtraHeaders can reintroduce conflicts.

Errors, performance and concurrency

Assignment is constant-time. Generation can fail through ordinary mail encoding/I/O paths and must not race with mutation.

Related entries

External references

Created 2026-07-15