This is BLFS-BOOK version r12.4 dated August 31st, 2025. This is the systemd branch of the BLFS book, currently targeting the LFS systemd book. For development versions, if this version is older than a month, it's likely that your mirror hasn't been synchronized recently and a newer version is probably available for download or viewing. Check one of the mirror sites at https://www.linuxfromscratch.org/mirrors.html for an updated version.