The upgrade got to Step 4, but is now stuck. What do I do to complete the upgrade? 

Screenshot: 

 

Any errors in the browser console?

Are you running the supported PHP versions: 8.0 and 8.1?

It is possible that they are using a CDN out of the data center Wasabi is in Northern Virginia.  Those are the same errors I am getting with my CSS and JS being served out of there.  If whitelisting doesn't work, you may need to remove it to continue the upgrade or wait until the CDN issue is resolved.  I imagine a good number of websites are experiencing issues right now.

It would be your IP you need to provide, you are being blocked from performing the upgrade process.

 

Okay, they whitelisted me, but now I'm getting a brand new error:

 

Would need to ensure that all those files are uploaded correctly to the server. You can download the full file set from the Client Area and overwrite those on your server.

 

They are uploaded correctly on my server. What should their permissions be? Currently they are 0644.

Would ensure that they are by re-uploading and ensure they are not erroring out. We cannot tell you what the permission should be as that really depends on the server. However, common configuration is 644. You would also want to contact your hosting provider to ensure the file is owned by the correct user/group

 

I downloaded the current stable release, but am getting an error message when I try to open the zip:

 

You would want to try again and ensure that you have a system which can unzip zip folder.

 

I do have a system that can unzip a zip folder. I do it all the time. I just now unzipped another file that's on my system as a test. But for some reason, this Invision zip file won't unzip for me. Is the complete zip file only 14.1mb?

Depending on the applications you have it will be around there, yes. I am not having any issues extracting the zip file in the client area. Please ensure you are awaiting for the full file to download before attempting.

403 Forbidden is error coming from your server, not the software. If you did not upload the files in the correct spot something may be off, unfortunately, it is not something we can provide support on. If you are unsure how to upload files, please contact your hosting provider to ensure they overwrite their existing counterparts on your server.