As I write these lines, iOS7's share is above 70%. And I feel about 30% more stupid because I made a sizeable mistake.

Supporting both iOS 6 and iOS 7 is a pain in the ass. I won't go into detail here on why since if you care about it you already knew it.

With iOS 7 soon on most Apple devices, it sounds like the time has come to dump iOS 6 for any new project. But what about old projects ?

I recently read – ok, misread – in news outlet that you could now publish an iOS7 version of your app with no regret because iOS 5 & 6 devices would still get the old version of your apps. This sounded like great news because previously the inability to serve old users had forced me to keep a lot of legacy code.

So I published a last iOS 6 update for all my apps, updating third party libraries etc, to make sure they'd remain functional for at least a year. I considered that after this iOS 5 & 6 wouldn't matter that much. After all at worst iOS 5/6 users would get this rather recent version.

After this got approved, I happily I published and update to my famed Battery app requiring iOS7. I was hoping that iOS7 users would get the new update and that people on older devices would just get the old version.

I even tested this with my account on my old 3GS. I can go to the AppStore and it gives me the previous version. Yay? NOT.

That is sadly not the reality. Reading carefully Apple News from September 18, 2013 you can notice it clearly states that this is about re-download for existing users. Not new users.

So I reset that 3GS and tested from scratch. I searched for my app and I was relieved. It was there! But then I created a new account to reproduce the situation of a real new user. Then I faced an ugly alert box saying the app required iOS 7. Ouch.

The result of this mistake? Since iOS 7 is only on 70% of the devices my downloads for this app tanked approximately 30% immediately.

So summarizing again:

If you require iOS7 for your existing apps:

• you will NOT GET ANY NEW CUSTOMER using iOS 5 / 6
• you WILL LOSE 30% of your downloads
• this WILL KILL YOUR RANKING
• it may RUIN CHRISTMAS

Thanks go to @AlexandreTorres who helped confirm this.

As I write this, I am canceling all reviews that were waiting for my other apps and I will probably resubmit a version that runs on iOS 6 for this app.

Most of this post was about me being stupid. However I do I think Apple should allow users to get old apps even with new accounts.

Today, if you buy a used iPhone 3GS you will not be able to download most older apps. Unless you get some old account with it that is.