An app I use just updated and it no longer runs on my system. When I try to run the application I get the error: error while loading shared libraries: libgfortran.so.4: cannot open shared object file: No such file or directory
I looked on my system and only libgfortran.so.3 is available. Do you know what should I do to have the next version also? Which package should I install? (my system is ubuntu 16.04)
This is an inverse problem to R v3.4.0-2 unable to find libgfortran.so.3 on Arch
So you must install GCC 7 including the Fortran part, that includes libgfortran 4.
There are answers describing how to do that at other StackExchange sites:
You should do the following for solving the problem
sudo add-apt-repository ppa:jonathonf/gcc-7.1
sudo apt-get update
sudo apt-get install gcc-7 g++-7
sudo apt-get install gfortran-7
来源：https://stackoverflow.com/questions/46516394/how-to-install-libgfortran-so-4-on-ubuntu-16-06