I have not upgraded my Notes on my iPhone 6 yet. I'm scared that I'll lose some of them; as some were created several phone versions ago. Has anyone that has upgraded encountered issues with losing any of their's?
Haven't lost any notes, only the ability to sync them with Microsoft Outlook. I had to start using iCloud to keep notes synced between my iPad and iPhone, but cannot sync notes with MS Outlook ever again.
I too have turned on the Notes update, and have lost no existing notes. But what I did gain are some great new options and features in Notes. I also added Notes to iCloud so I can access the Notes from my iPhone, iPad, and iMac, as well as iCloud via any browser.
There's nothing to lose, and everything to gain, by updating Notes.