We use OpenSSL to provide SSL/TLS communications. The version of OpenSSL we provided with version 13 had limited support of TLS1.2, whereas full support of TLS1.2 in OpenSSL (including Suite B) came out in the version of OpenSSL we shipped with version 14. You can see what each version of OpenSSL contained at https://en.wikipedia.org/wiki/OpenSSL
Now whether the limited support of TLS 1.2 that was included in the OpenSSL version in PxPlus 13 will be adequate for you is unknown -- we only know that full TLS1.2 support came out in the OpenSSL version shipped with V14.
Also, we only provide OpenSSL with Windows installs, on Linux and other OS'es we use whatever OpenSSL libraries exist on the OS thus you need to look at what your OS provides and use a version of PxPlus that was designed for use with that OS.
As for the documentation, the online documentation is for the current release and generally only the last and recent additions to the language are reflected. To show each and every change and enhancement in the current online help would make the documentation unreadable. We do provide all the prior help files in the Windows downloads for all prior releases back to the first version of PxPlus on our Archive site at:https://archives.pvxplus.com/PxPlus.Development.Suite/PxPlus/