Thank you very much for your continued support of back number.

Due to the discovery of a serious security vulnerability in PHP, a programming language used on many websites worldwide, we have been conducting emergency maintenance since October 21st to protect the security of our customers' information and services.

Subsequently, we implemented all possible security measures and strengthened our monitoring system before resuming service.

We will continue to strengthen our countermeasures and update our systems.

Please note that if any new problems are discovered, we may need to perform emergency maintenance again to ensure safety.

■ Service resumption date and time

Thursday, October 22, 2026, around 12:00 PM

■ Features that are still under maintenance

• Email newsletter

バースデー email

Due to the service provider's response status, some of the above features remain unavailable.

We will inform you again as soon as we have a date for reopening.

Furthermore, no information leaks related to this matter have been confirmed.

We sincerely apologize for the inconvenience and trouble we have caused over such a long period of time.