Activate iCloud+ Storage upgrade notification won’t go away having 4GB remaining

You can get rid of "one time" nags (like "Set up Apple Pay") by going into the screen in Settings, then cancelling out without actually setting up the feature, or subscribing, or whatever.

If you've done that and you keep getting the nags, see lobsterghost1's comments. You might discover that backups are not being done, syncing of photos to iCloud Photos is being paused, etc. for lack of enough free iCloud space.

Yes, if you're down to your last few MB, that's why you're getting the warnings. Is cost a concern to you? You can move up to 50GB of iCloud Storage for $1 a month? I find it wonderfully convenient knowing if something goes wrong, I can restore 100% of my data back to my phone if I need to. I'm also a big believer in redundant backups. I too back up to my Mac, but I still want my iCloud backups as I could be in a location, where I don't have access to my Mac and my need to restore my data.

Can you actually successfully backup your iPhone to iCloud? 5GB isn't much space, especially if you have a LOT of data on your iPhone. My guess is your backup exceeds the available space you have, which is why you're being prompted to move up to the next level of iCloud Storage, which you can for about $12 a year.

Luke Hopkins wrote:

I can backup my iPhone to iCloud because I've disabled images because my library is over 400GB. It's just too much to backup to the cloud, even the data usage

If you have disabled iCloud Photos, and you have also disabled the inclusion of photos in iCloud backups, I hope that you are manually importing new photos to a computer on a regular basis. (And backing it up.)

If those 400 GB of photos exist only on the iPhone, it would take only one catastrophe such as

• The iPhone being lost or stolen
• You forgetting your passcode, and being forced to reset and erase the iPhone to get back in
• Dropping the iPhone and breaking it

for you to lose all 400 GB worth of photos. Then it would be too late to decide that your photos are valuable to you. They would be gone no matter how valuable they were to you.

There is a thread on Reddit about this issue that is gaining traction. It is widespread and lots of us are having the same error.