Debian 12.3 was delayed due to an EXT4 data corruption bug that briefly appeared in the released Linux 6.1 LTS version. Debian 12.4 replaces Debian 12.3 and fixes dozens of bugs.
Debian 12.4 was released to replace Debian 12.3 after the introduction of Linux 6.1.66LTS. It was not affected by the EXT4 data corruption bug in previous releases.
Due to a problematic patch backported from Linux 6.5 that caused interference between EXT4 and iomap code, data corruption bugs may appear on older kernels - most notably the recent Linux 6.1 LTS minor version, which can currently be found in releases such as Debian 12.
A "subtle interaction" between Iomap and EXT4 has been blamed for the bug, which could lead to EXT4 file system data corruption and was discovered in Linux 6.1.64 and 6.1.55 minor releases. The new Linux 6.1.66 minor version has restored the problematic commit.
Debian's bug report on the matter describes it as "non-serious data loss", so it should be recoverable. But the timing was wrong, because Debian 12.3 was supposed to release the affected kernel version, so now it has delayed the release of subsequent versions.
Debian 12.4 fixes a local privilege escalation vulnerability in Amanda, Emerald theme-based artwork in Debian Edu 12, Unicode 15.1 support in different components, Zstd compression support in libsolv, and dozens of other bug and security fixes.
For downloads and more information about Debian version 12.4, please visit Debian.org:
https://www.debian.org/News/2023/20231210