To install Filezilla 3.30, first download the updated version from here.
Go to the ~/Downloads folder.
cd ~/Downloads
Now uncompress the downloaded file.
tar -vxjf FileZilla_3.30.0_x86_64-linux-gnu.tar.bz2
Now, go to the newly extracted folder.
cd FileZilla3/
Install the missing libpng16 that FileZilla is requesting:
sudo apt install libpng16-dev
Setup the ubuntu-toolchain-r PPA for installing the correct version of libstdc++.so.6 that FileZilla is looking for.
sudo add-apt-repository ppa:ubuntu-toolchain-r/test
sudo apt update
sudo apt upgrade
Now, copy over the updated FileZilla files to their correct locations:
sudo cp -ravx * /usr/
Now launch FileZilla as normal.