How to update from Volumio1.55 to 2.0?

Due to I do not success to connect wireless network with Volumio 2.0 but for Volumio 1.55 ,I can start wireless easily .How to I updated from 1.55 to 2.0 without flash new SD card.?

Unfortunately you can’t. The changes in the software are significant, and you will have to write the new image to your sd card in order to upgrade.