diff --git a/pkgs/README.md b/pkgs/README.md
index 7c99f3f4418f..76c5766d6c39 100644
--- a/pkgs/README.md
+++ b/pkgs/README.md
@@ -347,7 +347,7 @@ There are a few naming guidelines:
 
 - The `pname` and the `version` attribute _must not_ contain uppercase letters — e.g., `"mplayer"` instead of `"MPlayer"`.
 
-- The `version` attribute _must_ start with a digit e.g., `"0.3.1rc2"`.
+- The `version` attribute _must_ start with a digit e.g., `"0.3.1rc2"` or `"0-unstable-1970-01-01"`.
 
 - If a package is a commit from a repository without a version assigned, then the `version` attribute _should_ be the latest upstream version preceding that commit, followed by `-unstable-` and the date of the (fetched) commit. The date _must_ be in `"YYYY-MM-DD"` format.