Should I continue to work with CodeIgniter in an existing project?

For the third year now, we have been offering the ImageCMS project, originally created on the basis of Codeigniter. During this time, much has changed in the framework market, especially the apparent decrease in the activity of the Codeigniter framework support and the great growth in the popularity of the Yii framework make us think. Disputes about the benefits of different frameworks do not subside. Let's try to correlate the issue of choosing a framework with ImageCMS and find out why we work with CI.
Several reasons that we consider essential in order to continue working with Codeigniter:

1. Codeigniter is easy to learn, there is excellent documentation, specialists who worked with php get in the know very quickly and start working with the system;
2. Our product community already has more than 1,450 people, and the system has been installed more than 20,000 times. After changing the framework, the update will not work for users and they will have to support two products at once, the old version is about a year old;
3. Performance and protection against hacking are, in principle, equally well thought out with a slight advantage towards Yii. Our choice has the main types of protection and, if necessary, allows the completion of additional ones;
4. It is worth evaluating the future prospects of frameworks. Let's make a small comparison:
   Today Google evaluates the trends of popular frameworks as follows.

CodeIgniter Trend

Trend Yii

Zend Trend

Thus, we see that although Codeigniter is inferior to Yii, especially in RuNet, nevertheless its popularity continues to grow, this framework is not going to give up positions in the future.
What are the capabilities of developers and communities. Let's take simple community statistics in forums:

Name	Yii	Zend	Codeigniter
Number of participants in the official forum	44188	16259	163700
The number of students of the Russian-language forum	2313	2373	2394

Number of participants in the official forum Number of participants in the

Russian-language forum

Now consider the strengths of YII and the pros of the transition:

• Caches with the ability to change backends (File, Memcache, etc ...);
• Separation of access rights;
• Models

To summarize, a team of ten people could refine Codeigniter in this regard in a month, with such a community resource, the framework is more than promising.
All these advantages can really reduce development time, but let's imagine that migration to the new framework will give us.
In this connection, the question is, is it worth working on a complete update of the framework for our project? I would like to hear the opinion of the habrasociety on this topic.