Salesforce has been on a big push lately to get users over to lightning. They've made it clear that new features will be lighting-only and are auto-migrating instances in the next release cycle.
That said, there are still many issues with Lightning: The UI is slow, many features that worked in Classic will not work with Lighting and in many situations you'll need to switch between Classic and Lightning to use Salesforce's full functionality.
In this post we'll outline how to quickly opt-out of the auto-transition that Salesforce is pushing for October of 2019.
To be clear, Salesforce is not sunsetting Classic anytime soon. There are too many orgs that depend on the functionality and UI of Classic and requiring everyone to switch to Lightning would be a bad move. Instead, they ask that you submit a ticket to opt-out. However, all they do is send you a link to a url that asks why you're opt-ing out with a target date to start using Lightning. Once completed, you're all set. No more auto-transitioning to lightning.
When you submit a case, this is what you recieve:
To prevent the note from appearing as well as to Opt out your Org on Lightning Auto Transition on September, kindly fill up the "Delay Your Auto Transition" survey on this link:
Here are the steps to guide you:
If you also need to stop Auto-Transition Emails about Lightning Upgrades:
So after that, you have succesfully delayed your Lightning Auto Transition for your Organization.
That's it! Once completed you're good to go