First have a directory for these libraries, for example I create a directory in home calling: fallback_libraries:
mkdir ~/fallback_librariesNext you should find the package on ubuntu that provides that library. For example I want to install libicudata.so.66 and this library is in package libicu66.
Then find .deb files link to this package. For this package we can download it from this link: http://archive.ubuntu.com/ubuntu/pool/main/i/icu/libicu66_66.1-2ubuntu2_amd64.deb.
Download it using wget: