FP 2 Factory Reset: What OS will be on the phone afterwards?

[AnotherElk]

A factory reset on the Fairphone 2 will only delete Apps and user data, it will not touch the OS.

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The Fairphone 2's factory reset ... or the lack thereof

I am not sure about this. As I know what a factory reset should do (and usually always did for me) is setting everything back to the “factory” state without any individual setup, just as it left the factory. Which brings me to the point that it most sure did not have any (possible [software] problems). Anyway I could have also got something wrong of your statement.

https://support.fairphone.com/hc/en-us/articles/115001610926-How-to-return-to-Factory-settings-on-my-Fairphone-2