Port Game from iT2D 1.5 to iT2D 1.6

I understand that the point of iT2D 1.6 is to enable us to complete our games on the old iT2D engine before starting afresh on the new T2D engine. However, I can't seem to find a good guide on how to port my game to the iT2D 1.6 engine. If one exists, can someone kindly point it out for me? Thanks.

So far here's what I've tried:

1. Directly open a 1.5 project file -> Failed to Open.

2. So I created a new 1.6 project and copied all my data, scripts, managed, and gui folder over to the new project. It opened this time, but when I ran it, the entire screen resolution is messed up and I have no idea why. Specifically:
a. My game was set up as a universal app so in the iOS settings the Target Platform is set to iPad Portrait
b. I ran the game in iPhone mode simulator. Previously in 1.5, it displayed the iPhone gui and iPhone resolution. Now in 1.6 it displays the iPhone gui and what appears to be the iPad resolution, so the two don't match up (my gui is on the top left hand corner.)
c. It didn't start on my Titlescreen scene, but instead on the scene I have open currently. So it ended up displaying the Titlescreen gui over a town, which is incorrect.

3. My gui buttons don't work anymore. Nothing happens when I click on them. Quite strange.

So please tell me what I can replace and what I can't replace during porting. For example, can we replace the main.cs or game.cs or profiles? Can we replace any code in the system scripts folder? Anything we need to watch for? Thanks.