diff --git a/semver.md b/semver.md
index 3f1e709..f5de2e8 100644
--- a/semver.md
+++ b/semver.md
@@ -87,10 +87,10 @@ associated normal version. Examples: 1.0.0-alpha, 1.0.0-alpha.1,
 1. Build metadata MAY be denoted by appending a plus sign and a series of dot 
 separated identifiers immediately following the patch or pre-release version. 
 Identifiers MUST comprise only ASCII alphanumerics and hyphen [0-9A-Za-z-]. 
-Build metadata SHOULD be ignored when determining version precedence. Thus two
-packages with the same version, but different build metadata, are
-the same precedence. Examples: 1.0.0-alpha+001, 1.0.0+20130313144700, 
-1.0.0-beta+exp.sha.5114f85.
+Identifiers MUST NOT be empty. Build metadata SHOULD be ignored when determining
+version precedence. Thus two packages with the same version, but different build
+metadata, have the same precedence. Examples: 1.0.0-alpha+001, 
+1.0.0+20130313144700, 1.0.0-beta+exp.sha.5114f85.
 
 1. Precedence refers to how versions are compared to each other when ordered.
 Precedence MUST be calculated by separating the version into major, minor, patch