Ubisoft has announced in a forum post that the Rainbow Six Siege beta has been extended another 3 days, due to user complaints that their beta codes were late or never arrived.
The post states that all invites for pre-order customers have now been distributed; those who did digital preorders won't need an email.
"The GOOD news is that for those who have received their access, the experience has been trending positively! We've been getting good feedback on the content of the beta, and matchmaking and server stability have already been improved. There are still a few issues to work out, of course, and we will continue to do that over the course of the beta. Given the current situation, we’ve made the decision to extend the Closed Beta by 3 days. It will run through Thursday, October 1st," according to the post.