Evenflo has established a rear-facing height limit of 40” for the Symphony All-in-One car seat. This change is retroactive. As long as your car seat has not expired, you may continue to use your Symphony All-in-One car seat in the rear-facing position until the child reaches 40 inches, 40 lbs or the top of their head is within one inch of the top of the car seat headrest in either of the two lowest positions. Once your child exceeds any one of these size requirements, she can no longer use this car seat in the rear-facing position. Please note that these size ranges for rear-facing use generally include children up to three years old.