diff --git a/docs/2. database-schema.md b/docs/2. database-schema.md
index 7a90bd2..8bf0b06 100644
--- a/docs/2. database-schema.md	
+++ b/docs/2. database-schema.md	
@@ -39,5 +39,6 @@ We will be documenting the known inconsistencies in the data below:
     - version =< 0.3.0: The commit hash has 7 characters `0.3.0+commit.8a23feb`
     - version 0.3.1: No commit hash: `0.3.1`
     - version >= 0.3.2: The commit hash has 8 characters `0.3.2+commit.3b6a4117`
+  - **Multi-binary toolchains:** `version` is not always a single compiler version. Toolchains built from several binaries store a composite string identifying the whole toolchain. For example ZKsync's `zksolc` drives a separate `solc` backend, recorded as `zksolc:<zksolcVersion>;solc:<solcVersion>` (e.g. `zksolc:1.5.10;solc:0.8.26-1.0.2`, where the `solc` part is the era-solc backend release).
 
 See discussed changes for the next v2 schema [here](https://github.com/verifier-alliance/database-specs/issues/30).