Ah thanks didn't see that. Ok implemented that however the same error is also occurring for Setvalue.

C:\mainwindow.cpp:19: error: no matching function for call to 'QProgressBar::setValue()'
connect(counting, &counter::Increment_Count, ui->progressBar, &QProgressBar::setValue());
^
so how am I supposed to correct QProgressbar so that it now works (in the Qt5 version of setting it)?