Q: iOS 9 how to upgrade Notes if you selected upgrade later

Go to the Update page in the App store.  See if it offers an update.

Have a nice day.

This is not what @DML1 is asking.

After you upgrade to iOS 9 and you launch the Notes app for the first time (under iOS 9) it offers you the choice of upgrading your Notes store on iCloud to the new format.

I chose not to upgrade for the time being because of the following reason.

Once you upgrade any device that you are running an older system on; be it iOS 8, 7, 6 or OS X 10.10, 10.9, 10.8; will NOT be able to sync your notes anymore.

Previous Notes were stored in the iCloud email account. The new notes are stored in a separate file somewhere on iCloud.

So if you still have older devices or Macs running older systems (For example I still have a boot of Leopard on a separate partition to run older software), once you upgrade, the notes on your older devices will be out of Sync with newer devices.

The other thing is that if you use Notes a lot between your iOS device and your Mac; unless you are running El Capitan (which at the time of this writing is not officially released yet) you will also not be able to use your notes between your iPad and your Mac.

iCloud: Notes overview

Cheers, Andrew.

If you have an iPad 2 and you are updating Notes for the new sketch feature bear in mind the sketch feature only works with iPad 4's and newer.

Just one idea I had.

If you don't have the concern I outlined above and still want to upgrade Notes to get the new features…

Have you tried making sure all your apps are quit and going to your iCloud settings and signing out of iCloud and then (maybe rebooting your device) and then going back into iCloud settings and signing in again. Perhaps after signing in again and you open Notes you will be prompted with the option to upgrade or not again.

Let me know if this works!

Andrew.

Heres your answer.. its found on the apple website after days of digging

"If you upgrade later, your notes will stay the same, and you can upgrade to the new features at any time. Just open Notes and select Upgrade."

Upgrade your notes with iOS 9 and OS X El Capitan - Apple Support

Found that page.  I'm on 10.11.1 and 9.1 on MacBook 2012, iPad Mini and iPhone 4S, and can't find "Upgrade" to select in any obvious part of the UI. 

You need a iPad mini 2 for the sketch feature.

Thanks,  I read every disclaimer about requirements and do not find that in any Apple page that lists requirements for iOS 9 or Notes.  Plenty of other specifics on features with a higher floor.  Sloppy on their part to be sure. 

What's still puzzling is that I still can't find the upgrade option on any of the three devices - that should be independent of the ability to draw, and include the other new features. 

You're welcome. Here's some article, everthing I can find points to iPad 4 and above and mini 2 and above.

Upgrade your notes with iOS 9 and OS X El Capitan - Apple Support

And from the User Guide.

“Note: The sketching feature is available with upgraded notes on iPad (4th generation), iPad Air (all models), and iPad mini 2 and later.”

Excerpt From: Apple Inc. “iPad User Guide For iOS 9.” Apple Inc., 2015. iBooks.

This material may be protected by copyright.

Check out this book on the iBooks Store: https://itun.es/us/U4OT9.l

So just to be clear, if you already have notes open, tap the back arrow when you open notes and on the folders section you should see upgrade!