Why did Linux remove ISDN and old network drivers?

Linux merged a cleanup PR targeting legacy networking

Linux merged a change that drops the ISDN subsystem and other very old network drivers. The stated motivation is to reduce maintenance burden on core networking developers, because aging, niche code paths can complicate testing, increase the surface area for regressions, and slow down work on modern networking stacks.

What was removed

The merged pull request specifically eliminated the ISDN subsystem and a set of longstanding, rarely used network drivers. The accompanying rationale points out that “old code like amateur radio and NFC” has been a burden to developers working on core networking.

The practical impact

For typical users, these removals are most likely to matter only if they rely on hardware and software that used those legacy interfaces. If a system depends on ISDN, for instance, it would need alternative drivers or configuration approaches after the change. If someone uses mainstream networking hardware, Wi‑Fi, Ethernet, and modern telephony-related stacks, the impact is generally expected to be minimal.

Why it matters

Kernel driver churn is disruptive only for the minority of systems that still depend on obsolete components—but it can improve velocity and reliability for everyone else by:

• Reducing the amount of legacy code that must be kept compiling and working
• Making it easier to refactor or harden the parts of the kernel used by most networking workloads
• Lowering the risk that stale, unmaintained code contributes to security or stability problems

Overall, this is another example of the Linux kernel continuing its long-running policy: keep the tree healthy by removing antiquated subsystems when they stop being worth the maintenance cost.