On Nov 27, 2016, at 1:41 PM, Darac Marjal <mailinglist at darac.org.uk> wrote: > Firstly, that page states that UIDs should be 32-bit integers. If so, > why do there appear to be UIDs greater than 3 billion in the mailbox? Because 32 bits hold 4 billion decimal? 2^32 = 4,294,967,296 (this is why FAT32 has a 4GB file size limit).