In the process of developing a site on Yii1. Does it make sense to switch to Yii1 now or to think about switching to Yii2 right away?

Question

Yii

Right now, a very long development of one project on Yii1 is coming to an end. It so happened that the process dragged on for a period of more than a year. Yii2 came out in autumn. At that moment, a difficult decision had to be made, and it was made - to do it further on Yii1 (although, according to my ideas, not much work was done, but-but ...)
One way or another, the project will soon be completed, and then a developmental stage will inevitably follow. Adding many new features. With all this in mind, I have a question. How to be that it will be developed on Yii1?
Doesn't it make sense to switch to Yii2? I’m not a developer, I don’t understand all the nuances, so I can’t independently assess the complexity and scope of work. You'll have to trust the developer...
What is the best way to deal with such a situation? Do everything on Yii1 until we hit something? (are we stubborn?) Or not to increase the size of the project (number of functions and corny number of lines of code) to a larger one and immediately rewrite it to Yii2 if possible?

Answer 1

1. First release, then decide. Maybe the project will not fly at all from a business point of view ...
2. Once it flies, you can smoothly cover it with functional tests through some Codeception.
3. How to cover - you can smoothly rewrite and make sure that the tests do not break.

Answer 2

yii2 is already ready for battle.

Answer 3

Write down the pros and cons of switching to Yii2. You must know exactly why you need or do not need to change the version of the framework, then this question will not arise. And think in advance what will happen to the current code if you transfer it to Yii2, whether it will turn from a normal program into a mess of crutches