MMaps: Movement maps are generated from both maps and vmaps, and contain all the information to create an accurate line of sight checks and movement paths for creatures.
This has been updated and fixes a lot of bugs related to that.
VMaps: ("Virtual Maps") calculate the possibility of line-of-sight, as an example. Based on their content, the server can (for example) calculate if spell casts are possible (e.g. if a wall is in between the target and caster or not). This has been updated and fixes a lot of bugs related to that.
Automatic Backup System: A backup of the whole server, including your characters, is getting generated every day and stored on a separate server.