Epel has two types of Linux kernel package, kernel-lt and kernel-ml. What’s the difference between them?
The kernel-ml packages are built from the sources available from the mainline stable branch of The Linux Kernel Archives. The kernel configuration is based upon the default RHEL-7 configuration with added functionality enabled as appropriate. The packages are intentionally named kernel-ml so as not to conflict with the RHEL-7 kernels and, as such, they may be installed and updated alongside the regular kernel.
The kernel-lt packages are built from the sources available from The Linux Kernel Archives, just like the kernel-ml packages. The difference is that kernel-lt is based on a long term support branch and kernel-ml is based on the mainline stable branch.
Currently the most recent mainline stable release is 4.8.15, and the long term support releases for kernel 4.4 series is 4.4.39.