Earlier today Linus Torvalds merged a pull request to remove AX.25 and hamradio subsystem support from the Linux kernel. While the headline sounds ominous, most modern AX.25 implementations occur in software at the user level without relying on the kernel level implementation. Direwolf, for example, does not require kernel level AX.25 support. Other software relying on AX.25 may take advantage of dedicated AX.25 Python libraries.
The change comes as a result of AI based bug detection services capable of identifying critical issues among code that may no longer be maintained or utilized by end users. Torvalds stated that the amateur radio related code in the Linux kernel no longer had any active maintainers:
Amateur radio did have occasional users (or so I think) but most users switched to user space implementations since its all super slow stuff. Nobody stepped up to maintain the kernel code.
According to typesense the last Linux kernel commit related to AX.25 was 6 years ago.
Additional code removed includes ISDN support, bus mouse support, and various network drivers including support for old 3Com devices.
Source: Phoronix