+mailsort

From Elendor

 Syntax: +MAILSORT [@<altname>] {AUTHOR | SIZE | SUBJECT | TIME}

 This command resorts the mail in your mailbox by the indicated field. For 
 example, specifying AUTHOR sorts it alphabetically by author. It's most 
 common use is to resort your mail by TIME if somehow it gets sorted out of 
 order.

 Example: +mailsort time
   (Sorts the mail in your mailbox from least to most recent date of writing.)