As of last night the SailfishOs Qt5 Alpha is now available for download.
The biggest and most obvious change is that the "old" alpha used Qt 4.8.3, the "new" alpha uses Qt 5.
Equally interesting, X11 has been replaced by Wayland.
Whereas Qt 4.7.4 (Harmattan) and Qt 4.8.3 (Sailfish Silica) were close enough as to make very little difference, Qt5 brings some big changes. It remains to be seen as to how this makes supporting an app with a common code base for Harmattan and Sailfish more difficult (or even impossible….)
Sailfish have added a webpage on porting from Harmattan. It can be found here.
In the meantime I have installed the Qt5 Alpha on OSX and Lubuntu 64 bit, and been able to run and deploy the default "Hello Sailor" app on both. Windows is downloading in the background as I type this.
Note that before you install the new SDK, you should first deinstall the old SDK using the SDKMaintenance tool. As I am by nature suspicious I simply renamed the original install directory and the hidden .scratchbox2 directory, so that I could easily restore these if required.
My next step is to try running Landed and LandedSettings.. I hope to bring news over the next few days of how this works.