Nom 5 is out. It claims to be a bit more efficient and more developer friendly.
Unknown at this time how much effort it would take to switch.
Updated by Pierre Chifflier 7 months ago
Small update on this: most of the update has been done, and pushed on https://github.com/chifflier/suricata/tree/dev/nom5-v1
This is a rather intrusive update, only the first part is done here (basic upgrade to nom 5). A second PR will be written later to update parsers to use functions and closures instead of macros, but has been split for readability/review reasons.
Some unit tests (cargo test) broke, and are being fixed.
Sidenote: having unit tests in cargo test is great for spotting these kind of regressions, we must encourage people to write them!