Upgrading to Version 9 from 8

I am trying to migrate a solution from Version to Version So I created a solution on version 8 with all the dependencies and tried to upload it on the version 9 using service-center. It seem to be doing something for long time but nothing is uploaded and no error message ? What is the outsystems recommeded way of upgrading from version 8 to 9 ? 

How large is the solution?

And try to remove all system components from the solution, they are not needed and are a risc to screw up the 9 platform.


Do you even see anything in the Solution 1CP progress page?

Something like:

Best regards,
So I removed all the system components and tried to publish again. Still same result. 

Size : 12 MB

It is stuck on step 1. Please see attached image. 
I was able to upload it by doing one espace/extension at a time. 
You probably need to increase the size of your allowed uploads for your Web Server to accept a 12 MB file.