The Postgres Pro 9.5.18.1 sources can be obtained from the download section of our website: https://postgrespro.com/products/download. You should get a file named postgrespro-9.5.18.1.tar.gz or postgrespro-9.5.18.1.tar.bz2. After you have obtained the file, unpack it:

bunzip2 postgrespro-9.5.18.1.tar.bz2
tar xf postgrespro-9.5.18.1.tar

This will create a directory postgrespro-9.5.18.1 under the current directory with the Postgres Pro sources. Change into that directory for the rest of the installation procedure.

You can also get the source directly from the version control repository, see Appendix I.