Hi, yes I had a similar issue when upgrading to Qt6, I changed to using QStringConverter Because I sometimes I to build for Qt 5.15.2 my code looks like this example: ... // set the text encoding for the stream #if (QT_VERSION < QT_VERSION_CHECK(6, 0, 0)) ts.setCodec(bUtf8 ? "UTF-8" : "ISO 8859-1"); #else ts.setEncoding(bUtf8 ? QStringConverter::Utf8 : QStringConverter::Latin1); #endif ...

it worked. thanks @VRonin

Yes I use the builtin Qt zlib Thank you @ambershark I have added the following line in the quazip project .pro : LIBS += -lz Now I can compile it.

@mrjj Solve the problem loading the data is this way. QDataStream out(&dstFile); out.writeRawData(ba.data(), ba.size()); And works like a charm! Thank you!