还有别的方法可以直接升级么?
官網不鼓勵 在 stable 版本以前 升級到 Beta 版本
http://blog.linuxmint.com/?p=3035
Upgrade instructions:
This BETA release might contain critical bugs, please only use it for testing purposes and to help the Linux Mint team fix issues prior to the stable release.
It will be possible to upgrade from this BETA to the stable release.
It will also be possible to upgrade from Linux Mint 17.3. Upgrade instructions will be published
next month after the stable release of Linux Mint 18.