Wurst 7 is the seventh major version of Wurst and the first version to be based on Fabric instead of the MCP. Using Fabric makes it much faster to update Wurst 7 to a new Minecraft version. It also allows Wurst 7 to be compatible with snapshot versions and Fabric mods.
Wurst 7 is available for all Minecraft versions equal to or higher than Java Edition 1.14.2. Older versions are not supported by Wurst 7 because they are not supported by Fabric. For those older Minecraft versions, Wurst 6 is still being used.