LMDE is Linux Mint’s Debian based edition, which is usually faster and more stable than the normal editions based on Ubuntu.
New features in LMDE 4
- Automated partitioning with support for LVM and full-disk encryption
- Home directory encryption
- Support for automated installation of NVIDIA drivers
- NVMe support
- SecureBoot support
- Btrfs subvolumes support
- Revamped installer
- Automatic installation of microcode packages
- Automatic resolution bump for the live session to a minimum of 1024×768 in Virtualbox.
- Linux Mint 19.3 improvements (HDT, Boot-repair, System reports, language settings, HiDPI and artwork improvements, new boot menus, Celluloid, Gnote, Drawing, Cinnamon 4.4, XApp status icons…etc)
- APT recommends enabled by default
- Removed deb-multimedia repository and packages
- Debian 10 Buster package base with backports repository
More info in the official announcement.