We recently upgraded our attachment interface in 2 key ways:

1. We now automatically strip out the ‘ character from document names (like John’s Calendar.doc). This caused some problems previously and essentially halted the message from being delivered to anyone in the recipient list. So go ahead – name your document whatever you like – we’ll make sure it gets delivered!
2. Microsoft has recently changed the file format/extensions for their Office documents, including Word, Excel and Powerpoint. Since we accept three as uploads, we have added the following document extensions to our “allowed” list: .docx, .xlsx, .pptx