Extend the README, add instructions and support period

README.md

@@ -22,11 +22,47 @@ approach, and while all header files have been ported (and successfully
 compile), some preprocessor artifacts still need to be ported (currently
 commented out and tagged with a `FIXME` note).
 
-The latest version of this package aims to provide compatibility with
-[current versions of OpenSSL](https://www.openssl.org/news/changelog.html);
-to facilitate this, a build script will detect the OpenSSL version on the
-host system and configure the bindings appropriately. This will be done
-automatically when using these bindings with Dub.
+### Compatibility
+
+The latest version (v3.x and later) of this package aims to provide compatibility with
+[current versions of OpenSSL](https://www.openssl.org/news/changelog.html).
+
+The supported versions are all versions available on non-EOL Ubuntu LTS,
+which is roughly equivalent to a 10 years support.
+For Ubuntu versions under standard support, the version can be checked online,
+for example [here](https://packages.ubuntu.com/jammy/openssl).
+
+|    Ubuntu version    | OpenSSL version | Supported until |
+|:--------------------:|:---------------:|:---------------:|
+| 14.04 (Trusty)  | [1.0.1f](https://web.archive.org/web/20161208174333/https://packages.ubuntu.com/trusty/openssl) | April 2024 |
+| 16.04 (Xenial)  | [1.0.2g](https://web.archive.org/web/20161021100827/http://packages.ubuntu.com/xenial/openssl) | April 2026 |
+| 18.04 (Bionic)  | [1.1.0g / 1.1.1](https://web.archive.org/web/20161021100827/http://packages.ubuntu.com/xenial/openssl) | April 2028 |
+| 20.04 (Focal)  | [1.1.1f](https://web.archive.org/web/20210417090632/https://packages.ubuntu.com/focal/openssl) | April 2030 |
+| 22.04 (Jammy)  | [3.0.2](https://web.archive.org/web/20220606092159/https://packages.ubuntu.com/jammy/openssl) | April 2032 |
+
+
+To allow supporting multiple OpenSSL versions from the same D bindings,
+a build script exists to detect the OpenSSL version on the host system,
+which then writes a version file the bindings will use.
+This script depends on `pkg-config` being present, and is automatically
+invoked when building with `dub`.
+
+Other build systems can invoke the script directly and compile those bindings
+with `DeimosOpenSSLAutoDetect`.
+
+When using Windows or wanting to avoid the script,
+`dub` users should depend on the subconfiguration `library-manual-version`,
+and define the version in their dub file (e.g. `"versions" : [ "DeimosOpenSSL_3_0" ]`).
+
+A list of all available versions can be found in [deimos.openssl.opensslv](source/deimos/openssl/opensslv.d).
+
+Only minor versions are listen, patch versions are binary compatible with one another.
+We use "minor" and "patch" with the [intended SemVer meaning](https://semver.org/).
+For example, 1.1.1g and 1.1.1a are two different patch releases of the same minor.
+Since OpenSSL v3.0.0, correct SemVer versioning is used.
+
+All users not using the script should define the version corresponding to their OpenSSL version.
+In the event no version is defined, the bindings will default to v1.1.0h.
 
 ### License