Manual iPad update to iOS 15

If your iPad has iOS 12.5.4 on it and it is also showing that it is up to date, there is no way to manually update that iPad. It has the latest iOS that it will support on it. That would indicate you have either an iPad Air, an iPad Mini 2 or 3. Those devices are not capable of running iOS 15. If you want iOS 15, you would need to purchase a newer iPad.

Unfortunately, that model is not compatible with iOS 13 or higher.

The highest possible for that model is iOS 12.5.5.

Is there an issue using software updates directly from your iPad ? Or you can’t update because insufficient storage in your iPad ?