[Update: June 22, 16:30 (BST)]
The changes have been completed and pre-order codes can again be redeemed for PS4 Early Access codes. Users who requested a PS4 code during the changes will receive their code shortly by e-mail.

[Original News]
The option to redeem a pre-order code for a PS4 Early Access code on the pre-order code redemption website (https://redeem.finalfantasyxiv.com/eu) has been disabled on June 20 at 15:30 (BST) and will be unavailable while necessary technical changes are made.

[Date & Time]
June 20 from 15:30 BST

[Affected]
PS4 code redemption on Pre-order code redemption website