The Linux 3.18.9 kernel has its status been changed to LTS (Long-Term Support).
Linux kernel 3.18.9 includes updates for several CPU architectures, like x86, ARM, ARM64, MIPS, PowerPC, s390 and ARC. A numerous new drivers for Wireless, USB, Xen, SCSI, etc. are also included.
The new kernel also fixes some issues with the following file systems; JFFS2, Btrfs, NFS, XFS & OCFS2. Last but not least there are some enhancements for the network & sound components.
Greg Kroah-Hartman officially announced the 9th maintenance release of the Linux kernel 3.18 on March 7, along with Linux kernels 3.19.1, 3.14.35 LTS & 3.10.71 LTS. All these kernel releases included approximately the same enhancements.
Read the anouncement here.