Hello Kamil, I'm Keith and happy to help you with your question.
There is no requirement to register for VAT if your turnover is below 81K per annum. The result of Apple's actions will be that the buyer will pay a higher price for your products than was previously the case and this may affect your turnover. Of course, if the ultimate customer is registered for VAT or its equivalent in their own country they will be able to reclaim the output tax imposed by Apple as input tax in their accounts. I assume that Apple is not passing the VAT charged back to you when they pay you for your distance sales.
To be absolutely sure you could run the scenario past HMRC, their phone number is *****(###) ###-####and the relevant web site is:
I do hope I have been able to set your mind at rest over this matter.