Document versioning

docs/EVMC.md

@@ -6,7 +6,16 @@ On the Client-side it defines the interface for EVM implementations
 to access Ethereum environment and state.
 
 
-## Modules
+# Versioning {#versioning}
+
+The EVMC project uses [Semantic Versioning](https://semver.org).
+Moreover, the _MAJOR_ version number is also referenced as the EVMC ABI version.
+This ABI version is available to VM and Host implementations by ::EVMC_ABI_VERSION.
+For example EVMC 3.2.1 would have ABI version 3 and therefore this project release
+can be referenced as EVMC ABIv3 or just EVMC 3.
+
+
+# Modules
 
 - [EVMC](@ref EVMC) 
    – the main component that defines API for VMs and Clients (Hosts).

include/evmc/evmc.h

@@ -23,7 +23,14 @@ extern "C" {
 
 enum
 {
-    /** The EVMC ABI version number of the interface declared in this file. */
+    /**
+     * The EVMC ABI version number of the interface declared in this file.
+     *
+     * The EVMC ABI version always equals the major version number of the EVMC project.
+     * The Host SHOULD check if the ABI versions match when dynamically loading VMs.
+     *
+     * @see @ref versioning
+     */
     EVMC_ABI_VERSION = 6
 };