Iphone 13 can´t backup with ALL APPS DISABLED. It's mandatory to upgrade ICloud+?

Here is the Apple Support articles on what’s backed up.

https://support.apple.com/en-us/108770

Backup methods for iPhones.

https://support.apple.com/en-us/108771

Here is the Apple Support article on how to manage your iCloud storage.

https://support.apple.com/en-us/108922

Lastly, here’s the Apple Support article on the difference between iPhone storage and iCloud storage.

https://support.apple.com/en-us/102670

I think I confused the discussion by stating they were incremental. In the true sense of the word incremental no, what I failed to clarify (clearly state) was the difference between full backup and differential (not incremental) backups.

For example, I don’t sync photos. My first backup will backup my photos. My next backup only backs up new photos/changes not in the previous backup. So, your original/first backup backs up everything you’ve selected and not synced. The next backup will add to the backup new data, overwriting old data if necessary.

https://discussions.apple.com/thread/250465614

Here are 3 options for you to attempt to get the backup size recalculated.

1. Turn the iCloud Backup off, then back on.
2. Go to Settings > [name on top] > iCloud > iCloud Backup, and choose Backup Now. You may get an error that there is not enough space available, but it may then recalculate the backup size.
3. Perform a Force Restart to clear cache and do some basic housekeeping.

• Press and quickly release Volume up
• Press and quickly release Volume down
• Press and HOLD side button until the Apple logo appears. This may take up to 15 seconds while holding the side button before you see the Apple logo and you have to ignore anything else on the screen include the Slide to Power Off prompt. If you don't see the Apple Logo, then try again as it may take a couple of attempts to get the speed and sequence of the key presses correct.

This looks uncommon. I use a 13 Pro for testing purposes. Very lean, only the necessary stuff on it.

it has a 143MB back-up, with no apps selected. (My 17 Pro with all -but 2- apps selected has a 2.4GB)

Check what the size is of existing back-ups in your iCloud, and you may delete them to free up space.

My 13 Pro has been on iOS 26.x (betas) since they became available. I personally never did regret that upgrade.

There are quite some users vocal online about what they don't like about (any) update. It is an annual perpetual process. I always form my own opinions. Knowing that 99.9% of the complains represent 0.1% of the total users (okay, I made that up, but you get what I am saying)

topi127 wrote:

I don’t want to risk updating without having a proper backup first. Is upgrading to iCloud+ mandatory just to back up basic data like authenticators?

Back your phone up to your computer.

Back Up iPhone

Log out of your iCloud account, restart your device and then log back in.

Are you using a VPN or ever had VPN software on your device? If so, delete software, delete VPN profile, and reset network settings.

Your screenshot says you’ve never backed up before. Is that accurate? My recollection is the first backup pretty much has to backup a lot, then subsequent backups are smaller.

The first iCloud backup is just the first “full - meaning large” snapshot; subsequent backups are incremental, updating only what changed since the last backup. The types of data included are the same; only the amount of data transferred is different on later runs.

topi127 wrote:

If I expressed it wrong, I actually back up my iPhone by plugging it into my Mac and using Finder. It does require disk space, but this method works as a proper backup, not just a copy. The first backup saves everything from my iPhone, and subsequent backups are incremental, only storing changes. So I could restore my data. This method basically does the same thing as a standard iCloud backup, just on my Mac’s storage.

Mac backups of iPhone are full backups, not incremental.

Time Machine itself does incremental backups, including of Finder iPhone backups, but a Finder backup of an iPhone does not. It is a full backup.

If your Mac is reporting insufficient free storage, then start the Mac into Safe Mode, restart, and test again.

Yes but it says the next backup size is 6.24 GB. You only have the free 5GB. How is 6.24GB supposed to fit in 5GB?

Pay a dollar a month and buy 50GB iCloud plan, or backup someplace else.

There is the option of manually backing up your iPhone to a Mac or a Windows PC. However, if you choose to do that instead of synchronizing and backing up data to iCloud, you'll need to have the discipline to update backups often enough for them to be useful.

For me, it is worth a a few dollars a month to ensure that I have enough iCloud+ storage space to let me use iCloud synchronization and iCloud backup.

topi127 wrote:

I already paid for my iPhone and MacBook, which have more than enough local storage for backups. The issue isn’t about buying more iCloud space—it’s that the free 5 GB plan can’t even handle backing up an iPhone 13 with 0 apps selected. If the point of a free plan is to let people back up their devices, this one fails at that basic purpose.

Whatever you think is the moral situation, 5GB is not intended to be big enough to back up an phone, but if you paid a dollar a month 50GB would be big enough.

Backing up costs money in the real world.

How much internal storage is being used? Settings > General > iPhone Storage

No previous backups? The only way to mark data as valuable is with backups. Otherwise, one dunk, one drop, one fire, one loss, one theft, and it’s all gone.

Local storage is not a backup, it’s a copy. If your device is lost, stolen or damaged, your so called backup is also gone and useless.

Your first backup will backup the iPhone, subsequent backups are smaller. Your device clearly shows first backup is being performed.