AttachmentName and AttachmentContent keywords have been added to the search in the Mail section of the program, so you can now look for words directly contained in the attachments.

In the new All Attachments view (PRO) you can easily sift through the files directly - you can sort through files based on type, account or the item type it was originally attached to.

You can use full text search in eM Client for documents such as Word, Excel, PDF etc.