Unable to use the Solver on macOS Sierra 10.12.6

Hello everyone!
I am getting this error whenever I try to start ngsolve app:

/Applications/Netgen.app/Contents/MacOS/startup.sh ; exit;
dyld: Symbol not found: __ZdaPvSt11align_val_t
Referenced from: /Applications/Netgen.app/Contents/MacOS/libngcore.dylib
Expected in: /usr/lib/libc++.1.dylib
in /Applications/Netgen.app/Contents/MacOS/libngcore.dylib
/Applications/Netgen.app/Contents/MacOS/startup.sh: line 10: 27048 Abort trap: 6 $Netgen_MACOS/netgen

I have used the following parameters (as suggested by the site):

export PYTHONPATH=$PYTHONPATH:/Applications/Netgen.app/Contents/Resources/lib/python3.8/site-packages:.
export NETGENDIR=/Applications/Netgen.app/Contents/MacOS
export DYLD_LIBRARY_PATH=$DYLD_LIBRARY_PATH:$NETGENDIR
export DYLD_FRAMEWORK_PATH=$DYLD_FRAMEWORK_PATH:$NETGENDIR/../Frameworks
export PATH=$NETGENDIR:$PATH

I have python 3.8. Please help to fix the error. I am installing it on my laptop macbook pro.

Thank you.

Hello!

Netgen/NGSolve is written in C++17, which is not supported on MacOS 10.12 (at least 10.14 or 10.15 is needed)..

In case you cannot do a system upgrade for some reason, you may want to try older versions of NGSolve:
www.asc.tuwien.ac.at//~mhochsteger/ngsolve/macos/
Note that older versions are also depending on older Python versions (3.6 or 3.7).

Best,
Matthias

Thank you Matthias!

I was able to install ngsolve (older version: NGSolve-6.2.1901). But I have not problem in using the jupyter extension. When I use jupyter nbextension install --user --py ngsolve, I get the following error:

KeyError: 'The Python module ngsolve is not a valid nbextension, it is missing the `_jupyter_nbextension_paths()` method.'

And when I trying to use: python3 -c 'import ngsolve.webgui; ngsolve.webgui.howtoInstallJupyterLabextension()'

I am getting following error:
ModuleNotFoundError: No module named 'ngsolve.webgui'

Please let me know how to fix these errors.

Thank you.