Same here:
“Thank you for your patience as we review your application. Although we anticipated releasing your decision by March 15, the review process is taking longer than expected. Our holistic review process and careful consideration of each application sometimes makes for a lengthy review process. We anticipate releasing your decision by March 25.
When a decision has been released, you will receive an email notifying you that your application status has changed. You can then log into your application portal to view the decision.
Please don't hesitate to contact Admissions at admissions@crownschool.uchicago.edu with any questions. Have a great day!”