Hello I can’t update my iPhone to the latest versions

I don't recall a version 12.05, is that a type and you mean 12.5.5? Go to Settings > General > About > Version to check. An 6 series cannot be updated to iOS 13 or later as it does not have sufficient RAM to run it and it cannot be added.

What happens if you go to Settings > General > Software Update?

An iPhone 6 Plus isn't capable of 13 or above. If you've encountered an issue updating it to 12.5.5, describe it in this thread.

(219668)

andro144 Said:

"Hello I can’t update my iPhone to the latest versions: How can I receive update from apple my iPhone 6 Plus still in i0s 12.05"

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Updating an iPhone:

What to Update: Installed apps and the iOS.

How to do so...

A. Verify Compatibility:

Identify your iPhone model. The first thing that comes to mind in incompatibility being the culprit. So, confirm the model of your iPhone. If iPhone model is incompatible with iOS15 then it is because you iPhone does not meet the hardware requirements for this iOS version(s).

B. If Compatible...

1. Back Up First:

IMPORTANT: If you have an option to update, however, then be certain you backup your iPhone first. That way, you will have something to restore your iPhone from should anything go wrong with the update

then...

2. Proceed with the Update:

Go Here:  Update your iPhone Using a Computer - Apple Support

That is as far as you can update that iPhone. iOS requires more RAM than your iPhone has.

You can update to iOS 12.5.5.

Your unit doesn't have enough RAM for 13 or above.

(219670)

What does your iPhone say when you try to update ?

A 6s is new than a 6 by one year and has more RAM.

Did you read the responses in this thread?