Clear Other storage on iPhone 5s (12.4.9) impossible?

[f_herl]

I have an iPhone 5s (12.4.9) with system storage continuously growing after resetting my iPhone and trying all the other common hints on the web. For example, after my last reset (i.e., wiping everything and installing a backup) two days ago the system storage was down to 5GB, currently at 8GB (in between sometimes showing 12 GB, for whatever reason). In a couple of days my 16GB will be full again.

Apple states under https://support.apple.com/en-us/HT211686: "If you have iOS or iPadOS 13, your iPhone or iPad storage is full, and the storage is mostly taken up by "Other" storage, update your device to iOS or iPadOS 13.6.1 or later."

Since my iPhone can only run iOS 12, does this mean I will not be able to solve the problem without the update, or is there a different cause in iOS 12 and Apple above describes a iOS 13 specific problem only?

Thanks!

 

[sfphoto]

If you simply love the iP5s I would get another with an older iOS, i.e. 8,9,10.
If you simply love the size/operation I would get an SE gen1 as it is more capable of running 64bit that came with iOS11.

Article on storage:

How to Reduce “System” Storage Size on iPhone or iPad

If you have ever visited the iOS Storage section of Settings app on an iPhone or iPad, you may have noticed that the “System” storage section is occasionally quite large and can take up…

osxdaily.com