Also, according to the changelog, the u-boot build now comes from the denx.de mainline git tree, the Linux kernel has been updated to version 3.19.1-12-generic-bcm2709, I2C has been enabled by default in this build, and the settings from config.txt are now respected and used as described upstream.

You can download the second Snappy Ubuntu Core 15.04 edition for Raspberry Pi 2 from the official servers.