iOS 8, the next version of Apple's operating system software for the iPad, iPhone and iPod touch, is strongly expected to launch at WWDC 2014, starting on 2 June. But many users have been caught out, one way or another, by iOS upgrade launches in the past.

Some have upgraded recklessly and found that they don't like the new iOS, but can't go back because they didn't save the right files beforehand. Others have upgraded on launch day and hit massive server overload, making the process last for hours and occasionally losing apps in the process. You could be really unlucky and buy a second-hand iPad or iPhone shortly before a launch and then find it's too old to run the new software.

In this article we'll discuss the best ways to prepare for the launch of iOS 8, and how to avoid getting caught out like those poor unfortunates.

How to prepare for the iOS 8 launch: Which devices are compatible with iOS 8?

First things first: will you be able to download and run iOS 8 at all? Apple hasn't released this information yet, but we can get a fair idea of which iPads and iPhones will be able to run iOS 8 by looking at the compatibility lists for past versions of iOS.

We tackle this issue in more depth in a separate article - List of devices that will support iOS 8 - but we can summarise our prediction by saying that we expect iOS 8 to run on the iPhone 4s and later, the iPad 3 and later, the iPad mini 1 and later, and the iPod touch 5G. The iPad mini 1 is probably the most at-risk of those, but check the linked article for all the evidence.

How to prepare for the iOS 8 launch: Downgrading, and saving your blobs

Will you be able to downgrade from iOS 8 to iOS 7 (or, for that matter, iOS 6 or earlier)? Yes, probably - but it won't be easy, if history can teach us anything.

You could downgrade from iOS 7 to iOS 6 in the first weeks after it was unveiled but then the window clanged shut. Right now, the only way to downgrade is if you use one particular model of iPhone, and happened to save your blobs at the right time. Don't know what 'blobs' are? Lots of people don't.

If you're planning on upgrading to iOS 8, it might be worth finding out what they are, and getting into the habit of saving them - although, as I said, it's possible that you still won’t be able to downgrade because you're using the wrong hardware, or because Apple finds a way to close this loophole.

Now, there's been so much annoyance at Apple's strict downgrading policies that it's possible that things will get easier for iOS 8. But don't bet on it. We would suggest reading our article on downgrading from iOS 7 to iOS 6 carefully, to see what files you would need to have saved to pull off that process - maybe you can prepare for the next upgrade in such a way that downgrading is possible. But this isn't guaranteed to work; indeed, reading the article will also give you an idea of how hard it can be to reverse the upgrade, so you know what you're committing to.

Once we know more about iOS's details, we'll update our article How to downgrade from iOS 8 to iOS 7.

How to prepare for the iOS 8 launch

How to prepare for the iOS 8 launch: Joining the beta programme

One thing worth considering once iOS 8 is announced is joining the developer beta programme, which is likely to carry various advantages - although there are down sides too, and you'll have to pay for the privilege.

Obviously, you'd get access to the operating system (and consequent bragging rights) before it officially launches. (Although it will be an imperfect, unfinished version of iOS 8.) Moreover, iPhone and iPad owners who signed up to the iOS 7 beta could go back to iOS 6 if they didn't like it, using a downgrading process that was relatively simple. This may be the case with the iOS 8 beta.

But there are down sides to joining the beta, some of which are ethical - the beta programme is for app developers, not for iPhone users who fancy a look at unfinished software, or the opportunity to boast about having pre-release software, and a lot of blameless apps suffered with unfairly low review scores last time around because people who didn't know what they were doing signed up to the iOS 7 beta and then found that (obviously) many apps weren't yet optimised for it. Don't be like them. (On which topic, take a look at 'Please enjoy the iOS 7 beta responsibly'.)

How to prepare for the iOS 8 launch: Read the reviews, and try it out if possible

Ultimately the best plan for the iOS 8 launch is to frequently check tech sites you trust for reviews (our iOS 8 review will be posted soon after it launches), with details of new features and design changes from iOS 7, and then if possible (and if one of your friends takes the plunge) try the new software on a friend's device.

Bear in mind that hardware on the lower fringes of the compatibility list may only just be able to run iOS 8; iOS 7 caused performance problems with the iPhone 4, for instance, and you not get all the new features. Check for user reports from people using the same generation of iPhone or iPad as you.

In other words, make your mind up as far as possible, then upgrade. You don't want to be looking for ways to downgrade afterwards. It may be a free upgrade, but you should treat iOS 8 as a massively expensive purchase - because if you hate it, or your device struggles to run it, you've spoiled your experience with a piece of consumer hardware worth hundreds of pounds.

iOS 8 features wishlist: the changes iPhone and iPad users want in Apple's iOS 8

How to prepare for the iOS 8 launch: Upgrading

Our last bit of advance relates mostly to the way things happened with iOS 6, and we don’t expect this to be an issue this time around. But it's possible, and something to bear in mind.

When iOS 6 launched, Apple somehow underestimated user demand, and its servers struggled to cope. People found that upgrading took them hours and hours. Worse still, some discovered after the upgrade was complete that they had lost some apps.

These days losing apps is less of a worry because most of us download them through iCloud rather than syncing with a Mac. If an app disappears during the upgrade, track it down on the App Store on your iDevice and you should be able to redownload it at no cost. If this doesn't work, get in touch with Apple.

But for the lesser issue of slow upgrades, we’d suggest waiting at least a day before upgrading. This fits in with our general message of caution - you want to read about users’ experience with the new software and try it out on an friend's device or in an Apple store, so it makes to wait.

iPhone 5s with iOS 7

How to prepare for the iOS 8 launch: What if I hit problems?

If even all this preparation isn’t enough to protect you from an unexpected problem - you can't check everything, and it's possible that you didn’t notice some small but crucial element of iOS 7 that's been altered - then don't despair. Check online for discussion of the problem you’re having, since it's unlikely that you’ll be the only one experiencing it; other users may find a workaround, and there’s a good chance that Apple will deal with the issue in a subsequent update.

Finally, what we said to many iOS 7 haters who discovered that they couldn't downgrade was this: give it a chance. If there are major aesthetic changes, it's likely to feel weird at first. But when we go back to iOS 6 these days it looks horrible. Operating systems can grow on you.

More coverage of WWDC 2014

What else should you expect at WWDC 2014? Here at Macworld, we've got it covered.

Want to know what happened last year? At WWDC 2013, Apple unveiled OS X 10.9 Mavericks and iOS 7, both of which were released as beta versions after the event, as well as the new Mac Pro, a new MacBook AiriTunes Radio, and iWork for iCloud.

Take a closer look at Apple's WWDC history in our slideshow of Apple's WWDC launches from the past 10 years.

This year, Apple is likely to unveil iOS 8, as we've discussed here, and OS X 10.10, as well as other new products such as a Retina MacBook Air, and maybe even an iPhone 6 and an iWatch.

The Complete Guide to the iPhone 5s & 5c is on-sale now. Click here for buying information.