So I spent the night updating the said modules, here is the PR:
https://github.com/christophhart/HISE/pull/212

Sadly the AppVeyor CI fails already for a while, I would have been curious if windows builds as well.

The streaming_example needs a few modifications as well (e.g. runThread()). I'll push a PR when I tidied it up a bit.

The createMemoryMappedReader I left out, since that might require changes in the rest of HISE ass well, but updating all of HISE to juce6 is a bit big task, especially as I am only interested in the sampler.

Let me know if that works for you or what I should change/improve. Would love to see that merged.

Cheers