In order to benefit from these new tricks of iOS 11, of course, you have to create enough space on the good old iPhones to install iOS 11 at all. Between 3.5 and 4GB, there are at least temporarily free-standing skis. This means the usual procedure: apps you do not need to delete, photos swap, caches of individual apps to destroy, if possible and if all this is not enough you can also use the rude means to try to download some useless app that is larger, as its own space, then iOS voluntarily clears the cache of various apps. Sounds counter-intuitive but. If you do not get enough free space, you can still install the operating system via iTunes.
The new operating system is ultimately smaller on most devices (iPad Mini 2), sometimes larger (iPad Pro), which seems to be mainly due to the actually available memory.
If you have done this somewhat annoying procedure, but it can soon go to the actual spring cleaning, because iOS 11 makes one in the future easier. The best feature: you can not only delete apps, but also outsource. The latter means that you can retrieve the data from the apps again, you should decide to need them again.
A further practical possibility for streamlining the memory is now the possibility of viewing and deleting larger attachments. What is meant by photos, videos, etc., which are rumored in the various apps. Mail and messages, of course, but this setting also finds attachments in programs not by Apple itself.
As a last resort, you can now delete old conversations, and delete the “chatter from yesterday” (over one year old) in one swing. We wish we had these features always had.
PS: And do not be surprised, your battery life would deteriorate after the new installation noticeably, it could just be synonymous with the reindexing, the iOS 11 first time.