Linux Kernel 5.11 includes Intel’s software guard extensions (SGX), graphics support for AMD Van Gogh and AMD Dimgrey Cavefish APUs, Intel DG1 graphics, and performance gains for Radeon RX 6800. There are also the usualy array of file-system improvements, espcially to btrfs and XFS.
Grub 2 typically gets overridden when you install Windows or another Operating System. To make Ubuntu control the boot process, you need Reinstall (Repair/Restore) Grub using a Ubuntu Live CD.
Ubuntu 12.04 was released on the 26th of April 2012, which just so happened to be a Thursday. From there on in, Ubuntu 12.04 Precise Pangolin provided millions of users all over the world with a free, stable, secure operating system.