iOS 9 is now here, but you may be struggling to download it due to the sheer volume of traffic or due to other issues, for example, your iPhone may only have 8GB or 16GB storage and that may mean that you don't have enough space for the download. If the latter is the case you should see a message saying that Apple will delete some of your apps to make space, and then let you download them again later, but if that sounds like a lot of extra work, there is a way round it - follow this tutorial and install iOS 9 via iTunes, you may find you get there a little quicker and with fewer hiccups and without any space constraints.

We've also heard that people are seeing a number of errors when trying to download iOS 9, so we will address them below - but we still think the best solution is to download via iTunes.

For most queries related to the iOS 9 update process, your first port of call should be our iOS update guide. This has all the advice you could possibly want, from preparing for the update, to the pros and cons of each version of iOS, to the possible problems you're likely to encounter and how to fix them.

This article is a bit more specialised. We'll be addressing one particular issue that lots of people have faced when updating to a new version of iOS: not having enough room on their iPhone or iPad to squeeze in the install file. (Apple says this will be less of an issue with iOS 9, both because its install file will be smaller and because there will be an automated tool to delete non-vital files and then reinstall them afterwards, but we can't imagine the problem will disappear entirely.)

Specifically we look at how to get round the problem of an over-full iDevice that can't fit in the latest iOS update file, we offer a simple and effective solution: update iOS on your Mac instead. Luckily this solution is great for the other problems we mention too.

(For a more old-fashioned approach to this problem, see How to make space on an iPhone when you need it.)

Read next: 31 brilliant iOS 9 tips and Advanced iOS 9 tips plus How to get the News app in the UK (How to use the News app) | How to use Apple's Notes app in iOS 9 | How to use Proactive in iOS 9 | How to search in iOS 9 | How to use public-transport directions in iOS 9 Apple Maps | Multitasking on the iPad in iOS 9

How to update iOS if you don't have space on your iPhone/iPad

This is what we had to do when it turned out iOS 8 required more space than we had available - the same wlll apply if you have the same issue. You can view a video tutorial for these steps at the top of this article.

You don't need as much space to install iOS 9. When we checked General > Software Update on our iPad we found that iOS 9 would take up 877MB but will take up to 1.3GB of space while it downloads. That compares to iOS 8 which was 1.1GB in size but required 5.8GB storage to be available to install. iOS 7 was even bigger.

Last time Apple helpfully suggested that you could make more storage available by deleting items, and this time round the company is actually offering to delete apps for you (and let you download them again afterwards). But if you are in a hurry then it may not be an attractive option. When it came to iOS 8 we had just 1.4GB available on a iPhone 5s. Sure, we could have deleted Music (3.6GB) and Photos & Camera (2GB) but that still wouldn’t be enough. And to be honest, we weren't keen to delete anything because we'd already slimmed down the iPhone considerably (having previously had a 64GB iPhone 5). Luckily there is another way.

Turning on the Mac and starting up iTunes gave us the message that "A new iPhone software version (8.0) is available for the iPhone "Karen's iPhone". Would you like to download it and update your iPhone now?"

Before clicking Yes, we quickly checked that the iCloud Back up was up to date. Last backed up on 14 September 2014 at 20.45 seemed a bit out of date, so we did a backup as that’s always a wise thing to do before updating. That took a few minutes.

Once backed up we clicked on Transfer and Update and the Mac began connecting to the iOS update server.

Then we clicked Agree to the software licence agreement. And when it asked for the passcode on the phone Touch ID was sufficient.

Here's where we wish it was quicker, when we tried this on the night iOS 8 launched, iTunes told us that there was 11, then 12, then 13 hours remaining. We're pretty sure that is longer than last year? We left it downloading overnight. Unfortunately by the morning the download had failed. Probably because the servers were overloaded.

This morning we started the download again. Things moved a lot quicker this time. Once the iOS 8 update had finshed downloading to our Mac, it then switched to updating the iPhone firmware, eventually restarting the iPhone at which point we had various set up options to run through before iOS 8 was ready to go.

You can follow the whole process in the video at the top of this article. It did take a while, but probably only about 40 minutes from beginning to end. With iOS 9 the update was even quicker, taking just half an hour on the day the update became available.

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