For quite awhile if you wanted to send a .exe attachment in Gmail you could rename the extension and it would go right on through. However, within the last couple of weeks these attachments are now being blocked. And it seems like it's only being blocked on some Gmail addresses, or from certain senders.
For example, I can send an email from aaa@XYZCorp.com to my own Gmail address with an exe attachment renamed to .exx, and it will go on through.
But an email from bbb@XYZCorp.com with the exact same attachment to the same Gmail address will be blocked.
I can send the attachment to my address OK, but sending to a different Gmail address gets blocked.