Linux kernel 4.3.4 is quite a small release that changes a total of 64 files with 486 insertions and 186 deletions. As mentioned, it is a maintenance release that brings mostly bugfixes, and just by looking at the diff from Linux kernel 4.3.3, we can notice multiple drivers updates, especially for things like USB, ACPI (Advanced Configuration and Power Interface), Character Device Drivers, and networking (mostly Ethernet, but also PPP, USB, and PHY changes).