Hi Julian, are you planning on updating GNU efi this release cycle? The new version will break compatibility (and definitely break syslinux builds). The compatibility breaking changes are all good by themselves as far as I'm concerned (e.g. jmp_buf is compatible with the C standard in newer versions [1]) and will allow me to drop some of the not-so-nice patches to the syslinux Debian package. (Some changes to the newer gnu-efi were contributed by the main syslinux author.)
My personal preference would be to update to the newest version, and to do so soon (if possible in experimental first). I'd like to avoid this update happening close to the freeze. Thanks Lukas [1] https://sourceforge.net/p/gnu-efi/bugs/17/