iPhone Transfer backup iPhone Jailbreak

[Dydy]

Before you start,
sorry if I'm wrong section and if I make mistakes, I am French ^^'

Hello !
I just purchased a iPhone 6 64GB iOS 8.4, so I would like to transfer my backup my old laptop, a iPhone 4S 16GB iOS 7.1.1 JB Pangu, via iTunes.
And this is where I have two problems, the first is that the iPhone 4S iOS 7.1.1 and iPhone 6 is iOS 8.4, is there going to be a problem in transfer backup as they are not the same version?
The second is that my iPhone 4S is JB, so if I transfer my backup to this iPhone 4S toward 6 via iTunes, and will this be a problem? Is it necessary to remove the JB in my 4S before my backup or JB is not reflected in the backup? Knowing that I do not want to "Restore" my phone because I do not want to lose all my backup.
There, there.
Thank you in advance for your answers!

 

[Applejuiced]

There's no problem restoring an older ios created backup to a newer ios running device.
Its only a problem would be lets say if the backup was made on ios 8.4 and you want to restore it to an iphone that runs ios 8.1 for example.
Its not a prob restoring a JB backup. You'd be fine.

 

[Dydy]

Thank you for your response !

And is it better than I uninstall all the tweaks before the transfer where there is no need?

 

[Applejuiced]

I wouldn't bother.