Can't compile NC client 3.8.1 from source

I used to compile the client from source on my KDE Neon system, no problems until 3.8.0. With 3.8.1 I get this error:

/home/user/src/desktop-3.8.1/src/libsync/clientsideencryption.cpp:1736:10: error: call to deleted constructor of 'QCryptographicHash' [clang-diagnostic-error]
    auto hashAlgorithm = QCryptographicHash{QCryptographicHash::Sha256};
         ^               ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/x86_64-linux-gnu/qt5/QtCore/qcryptographichash.h:106:20: note: 'QCryptographicHash' has been explicitly marked deleted here

It seems, your local Qt is too new in comparision to the Qt used to program the client with. maybe you should have a look at the compatible Qt versions.