Can anyone in-the-know shed some light on how notmuch generates its thread ids? Until recently, I'd only seen numeric thread ids 16 characters long, padded with zeroes. For example: thread:0000000000000001 thread:0000000000000002 thread:0000000000000005 etc etc Today, several new threads were created with non numeric ids: thread:000000000000000d thread:000000000000000e thread:000000000000000f Is this normal behavior? -- Rama