“Undo Send” matures from Gmail Labs to GMail feature
Sometimes, it is really necessary to have an Undo Send email after sending across an email. This occurs when you hit send by mistake while still you are composing the email or you sent it to wrong audience and noticed it immediately after sending the email.
Gmail labs had “Undo Send” option in place over the past few years and this has now matured into a option for all. To enable, visit the settings option in GMail at the right top of the screen and in General tab, you can find “Undo Send” option. Once you have enabled “Undo Send”, you can select the cancellation period of 5,10,20,30 seconds. You will have those many seconds to stop the mail being sent out of your mailbox.
When this feature is enabled, Google will not relay your email till the cancellation period is over. This enables user some amount of control over the email after it is send.
I had it enabled when it was a Labs app and I used undo send few times. Good to see it mature finally into a feature.