I was told the same but still got an email to the contrary at 14:36:
We hope you are looking forward to the start of the new season.
Please note that due to a higher than anticipated number of requests for physical season tickets, delivery of your 2023/24 season ticket will be delayed and will not be ready ahead of the opening game against Preston North End on Saturday, August 5th.
You will soon be sent an e-ticket via a confirmation email that you can use to gain entry at the Preston North End game. Your physical season card will be posted to you as soon as possible.
We apologise for any inconvenience and thank you for your support.