When you visit parts of the website of the Driver & Vehicle Licensing Agency in the U.K. outside of standard office hours, you will see this:

It seems ridiculous, almost like the famous 500-mile email bug, but Dafydd Vaughan explains how it came to be. It won’t be a surprise that the story starts with an old computer system, built around a day/night cadence where people would visit the agency during the day, the information would be collected, and all the data processing would happen overnight:

At the time, many of DVLA’s services – particularly those relating to driving licences were still backed by an old IBM mainframe from the 1980s – fondly known as Drivers-90 (or D90 for short). D90 was your typical mainframe – code written in COBOL using the ADABAS database package. Most data processing happened “offline” – through batch jobs which ran during an overnight window.

The team upgrading it in 2013 decided to not attack too many things at once, and swap the innards but keep the day/night system intact.

I’ll let you read some details inside if you are interested, and if you want to learn why the 2013 decision is still a 2026 (or at least 2025) reality. Like many of these, it is a story of heavy financial and technical constraints. But I will excerpt this bit, because I think many teams in any company – design systems, security, or “core” (whatever that happens to be) – would relate to it:

It’s difficult for an organisation to keep its focus and attention on a complex upgrade – particularly without getting noticeable benefits along the way.

The tricky part is that in many places you do end up in a legacy situation that is exactly as absurd as “an internet service having opening hours,” but you might be too close to the problem to even realize it.