Upgraded Notes do not sync with older notes
I have an iPhone 4 with ios 7 and bought a new iPad Pro with iOS 11.
When setting up the new iPad the notes app asked to upgrade. When accessing iCloud.com it asked the same.
in summary: iCloud and iPad have the newest notes with all advanced features. iPhone has the old version of notes with simple text only.
problem: i started deleting and rearranging notes in new folders using the new notes, but at the same time edited the text of some notes on iPhone. the changes from iPhone do not sync with the upgraded notes.
i have 2 notes with more text in iPhone that are not up to date in iPad or iCloud (updated notes).
how can I solve it?
iPhone 4, iOS 7.1.2