Im a little confused on the next gen implementation. Can anyone confirm that if I make changes to the next gen version, it wont impact the classic live app (providing I don’t make structural changes to the data sources)?
I can see that in the next gen version there is some cleaning up to do for me, such as rewriting the JavaScript etc, but I don’t want to do anything, if it will impact the classic app which is currently in use.
Hi @Chris8 - that’s a great question. 
I’ve sent a message to @JohnKaras and @Kara as I would also like to know the answer.
I’m sure there is mention of it in the documents somewhere, but as it’s such an important point I’m sure they won’t mind sharing here. I had a similar query from another client this morning.
Hi @Chris8
Next Gen and Classic share different resources and front end URLs. If you add javascript to Next Gen it will not affect classic and vice versa. This is because when looking at the front end you are on a different URL. So you can test your JavaScript in Next Gen without worrying that you are going to break something in Classic.
Users will only see Next Gen if you give them the new URL. In theory you can run the two apps side by side only giving the url to certain users when that area is ready. That will give rise to complications so I wouldn’t advise doing that unless you have completely thought through the ramifications.
As far as I am aware the apps only share the data so making changes to your objects/tables should appear in both next gen and classic.
Craig
Hello @Chris8 and @CarlHolmes
@CSWinnall is correct. JavaScript and CSS on Classic and Next-Gen do not affect each other. You can rewrite the JS in Next-Gen and it does not affect the Classic Live App in any way.
Additionally, in Classic, the “Look and Feel” settings do not carry over to the Next-Gen Live App, and Themes in the Next-Gen Live App do not carry over or make the Classic Live App look different.
Note: If you have colors, like Display Rules setting a background color or text, those do carry over from Classic to Next-Gen, you do not have to recreate those rules.
I hope this helps, please let me know if you need more clarification.
Thank you!
Kara
Thankyou for this. I noticed that the logo for the app did not carry over into next gen. when I updated it it did not impact the classic, however when I updated the minimal logo, it overwrite the classic app logo? I have since had to update the logo in the classic app, but this does not appear to have made any impact to either logo in the next gen app.
To check I wasn’t going mad, and somehow accidentally update the wrong one, I removed both logos from next gen and readded them, and had the same outcome. the classic app logo updates to the minimal logo from the next gen app.
Are there any other scenarios like this where i may break classic app functionality by amending the next gen app?
@Chris8 Thanks for letting me know - we will fix this.
@Chris8 We’ve been trying to replicate this issue and have been unsuccessful. I wanted to look at log files for when this happened to you, but I think the email you used to sign up in forums is different from the one used to sign into Knack. Could you send me (kara.peabody@knack.com) an email with the email you were logged into the builder with when this happened, and the app name as well?
Thank you!
Kara
Hi,
I have sent you an email just now. Thanks for looking into this.
Chris
Previously, at least, certain changes made to forms in NextGen are carried over to Classic. Haven’t tested that recently though.