If astap is installed via an APT-Repo then the following command works:
sudo apt-get update && sudo apt-get --only-upgrade install astap
wget https://sourceforge.net/projects/astap-program/files/linux_installer/astap_armhf.deb/download -O /tmp/astap_armhf.deb
sudo dpkg --install /tmp/astap_armhf.deb