jbron wrote:I don't want to upgrade "just for fun", but because I want to develop locally using PHP 7 and be sure that my local website will work properly once live.
If this is the goal, you definately MUST NOT use Windows. Windows is extremly uncommon in live environments for Apache/PHP/MySQL, most servers are running Linux. Many sophisticated tools arent available under Windows or require different configuration and management. To be sure, you really should go for Linux instead of Windows.
jbron wrote:So among the numerous higky skilled developers using Xamp, no one ever wrote a tutorial explaining the different steps for upgrading safely?
No, as there are no "higky skilled developers", as Xampp is NOT "developed" (i thought, i had explained it), it is "collected". The Xampp Bitnami team collects and preconfigures the tools and also provide an installation tool. There is no development, all these tools are developed separately. There is no "safe upgrade" due to the fact, that the user may change all configurations etc.. There is also the problem, that some configuration options (for Apache for example. with version 2.4 the "Allow from" clause has been removed and replaced by the "Require" clause) may change, there is no general advice how to manage such complex things.
If you think, that you are better skilled and can provide such an step by step upgrade documentation, feel free to join the Bitnami team.