Which can be both correct and wrong depending on context. Normally there is no such thing as a capital ß, so it was decided that if for some unreasonable reaso

Which can be both correct and wrong depending on context. Normally there is no such thing as a capital ß, so it was decided that if for some unreasonable reason you do uppercase it you go with SS. But then for some all-caps usages this is not right. E.g. a all caps name of an restaurant as placed above the restaurants door. In which case it was common to have a ß in a all-caps name like FOOßBAR. So they decided that for reasons like this we now have an (EDIT: semi?) official uppercase ß. So all in all this and other examples in other languages mean you should never do a case insensitive comparison by upper/lower casing both sides, it won't work reliable.