Hello and welcome! > On my system (Debian 10 - Buster) is OpenSSL installed with Version 1.1. > Now, I want to install OpenSSL 3.x, but which is the best way for that? > > Deinstall the old one, or? First, keep in mind that 3.x is still in alpha development stage, so using it as the system-wide library is not at all recommended. Even after 3.0 will be released officially, replacing the system wide installation of OpenSSL provided by your Linux distribution is a very risky business, as many of the required and optional binary packages the distribution provides are depending on the version of `libcrypto` and `libssl` shipped within the official OpenSSL packages from your distribution. The recommended thing to do when you want to build applications from sources to use a different version of OpenSSL than what is shipped with your distribution is to have a custom installation of OpenSSL (somewhere outside of your linker default path). You can read more about it on the NOTES.UNIX file in your source tarball, or at https://github.com/openssl/openssl/blob/OpenSSL_1_1_1-stable/NOTES.UNIX . Note the link above is from the 1.1.1 stable branch, as in master soon it will likely be replaced with a markdown version of the same file (PR #12109): you can see a preview of the markdown version of it at https://github.com/openssl/openssl/blob/be101175badd30402d2e480a79e98ade1343cbfd/NOTES-Unix.md but beware this link is likely going to be broken at some point after the PR is merged (but at that point you will be able to find the same file in `master`). Hope this helps! Best regards, Nicola Tuveri
