A easy question for Ci4.0 ( can i Upgrade from Ci3 to Ci4 ?)

I think this is one easy question, because i hope to sure for my project so i must create this topic question 

Question: 
I am in a Project which is building on Ci3.0.6, rummor about Ci4.0 will was born in next times, my question is may i update my Project from Ci3.0.6 to Ci4.0 ? ( My project about Mini Supermarket, i has only created files in Library, Helper, Controller and Models )

Please can tell me can i sure to Upgrade my Project from Ci3.0.4 to Ci4.0 ? That is very important to me because my Project will Complete at middle of next year but in that times the Ci4.0 can be republic 

Please help my small brian !  verry verry thanks

i am vietnamese so not pretty about english 

CodeIgniter 4 will not be backwards compatible with CodeIgniter 3.
There will be philosophical similarities, but the codebase will exploit PHP7.
There will be a section in the user guide about upgrading from CI3 to CI4, but it will definitely not be as easy as replacing the "system" folder.

CodeIgniter 4 will not be backwards compatible with CodeIgniter 3.
There will be philosophical similarities, but the codebase will exploit PHP7.
There will be a section in the user guide about upgrading from CI3 to CI4, but it will definitely not be as easy as replacing the "system" folder.

Can i move files in Library, Helper, Controller and Models to Ci4 for reuse ? 

3rd party or custom class's will be reusable if they work under PHP 7, but if you use some CI 3 features inside your custom libs, they may not work.

Best VPS Hosting : Digital Ocean

Also you better make sure that your hosting provider will run PHP 7 right now most do not they are only offering PHP 5.6.x

What did you Try? What did you Get? What did you Expect?

Joined CodeIgniter Community 2009.  ( Skype: insitfx )

Also you better make sure that your hosting provider will run PHP 7 right now most do not they are only offering PHP 5.6.x

Helpful: http://phpversions.info/php-7/

3rd party or custom class's will be reusable if they work under PHP 7, but if you use some CI 3 features inside your custom libs, they may not work.

  Oh, so thanks you !
My Ci3.0.6 Project only use helpers and database library of CI3.0.6, another features were builted by my Team ( created in Library folder of Ci3.0.9 ! be sure ), and with your sweet answer my Project can Move to Ci4.0, now i can free about my question caption 

Helpful: http://phpversions.info/php-7/

WOW - that is a great link because it shows the actual *version* of PHP 7 the hosting company is running.
A very good guide for which hosting companies do their updates. Thank you for posting.