Version: 1.10.92 (using Devel) Installed from: Compiled sources When I use the aggregation mode 'activity by date' threaded' and choose to group 'by Smart Date Ranges (of Thread Leaders) the folders get clogged with loads of messages in an "unknown" group. Some emails in a particular day/month go into a group for that day/month, whilst other emails in the same day/month are in unknown. If this is intentional it's pretty confusing! If not, then it looks like KMail is failing to recognise the dates or group them properly.
*** This bug has been marked as a duplicate of bug 179076 ***
Created attachment 29763 [details] Screenshot of bad grouping I have attached an image showing my inbox list. The three messages at the top are in the 'unknown' group but should presumably go into December and November folders.
I'm not sure that the third mail chould go into Nov, cause it's a plus sign before it and it might be that someone replied to the email in question during Dec, and hence to how the sorting works should also be in Dec. Not Unknown though. :)