diff --git a/readme.md b/readme.md
index b288b7df..9320340d 100644
--- a/readme.md
+++ b/readme.md
@@ -54,7 +54,10 @@ wasmtime run --dir=. src/dialogc.wasm story.dg stdlib.dg
 
 ## Release notes
 
-### 1c/04, Lib 1.2.4:
+### 1c/04, Lib 1.2.3:
+
+		Compiler: multiple definitions for the same style class or
+		metadata predicate (outside the library) now produce a warning.
 
 		Compiler: improved dictionary word matching accuracy.
 
@@ -63,7 +66,7 @@ wasmtime run --dir=. src/dialogc.wasm story.dg stdlib.dg
 
 		Documentation: Convert the repository readme to markdown.
 
-### 1c/03, Lib 1.2.4:
+### 1c/03, Lib 1.2.3:
 
 		Language: CSS text-decoration: reverse has been replaced with
 		-iftf-reverse-video: reverse for compatibility reasons.
diff --git a/src/ast.h b/src/ast.h
index 9e5be7b6..66279d5a 100644
--- a/src/ast.h
+++ b/src/ast.h
@@ -452,6 +452,7 @@ struct program {
 	uint16_t		max_temp;
 	uint8_t			reported_violations;
 	int				topic_warning_level; // WARN_*
+	int				lib_file; // Which file has (library version)
 };
 
 #define WARN_DEFAULT	0
diff --git a/src/backend.c b/src/backend.c
index d1782ba3..372901c2 100644
--- a/src/backend.c
+++ b/src/backend.c
@@ -300,7 +300,7 @@ int main(int argc, char **argv) {
 
 	need_meta = prg->totallines > 100;
 
-	prg->meta_ifid = decode_metadata_str(BI_STORY_IFID, 0, prg, &prg->arena);
+	prg->meta_ifid = decode_metadata_str(BI_STORY_IFID, 0, prg, &prg->arena, "story ifid", prg->lib_file);
 	if(!prg->meta_ifid) {
 		if(!strcmp(format, "zblorb")) { // Mandatory for zblorb, make it an error
 			report(LVL_ERR, 0, "An IFID is mandatory for the blorb output format.");
@@ -315,25 +315,25 @@ int main(int argc, char **argv) {
 		prg->meta_ifid = 0;
 	}
 
-	prg->meta_author = decode_metadata_str(BI_STORY_AUTHOR, 0, prg, &prg->arena);
+	prg->meta_author = decode_metadata_str(BI_STORY_AUTHOR, 0, prg, &prg->arena, "story author", prg->lib_file);
 	if(!prg->meta_author) {
 		if(need_meta) {
 			report(LVL_WARN, 0, "No author declared.");
 		}
 		prg->meta_author = "Anonymous";
 	}
-	prg->meta_title = decode_metadata_str(BI_STORY_TITLE, 0, prg, &prg->arena);
+	prg->meta_title = decode_metadata_str(BI_STORY_TITLE, 0, prg, &prg->arena, "story title", prg->lib_file);
 	if(!prg->meta_title) {
 		if(need_meta) {
 			report(LVL_WARN, 0, "No title declared.");
 		}
 		prg->meta_title = "An Interactive Fiction";
 	}
-	prg->meta_noun = decode_metadata_str(BI_STORY_NOUN, 0, prg, &prg->arena);
+	prg->meta_noun = decode_metadata_str(BI_STORY_NOUN, 0, prg, &prg->arena, "story noun", prg->lib_file);
 	if(!prg->meta_noun) {
 		prg->meta_noun = "An Interactive Fiction";
 	}
-	prg->meta_blurb = decode_metadata_str(BI_STORY_BLURB, 0, prg, &prg->arena);
+	prg->meta_blurb = decode_metadata_str(BI_STORY_BLURB, 0, prg, &prg->arena, "story blurb", prg->lib_file);
 
 	predname = find_builtin(prg, BI_STORY_RELEASE);
 	if(predname && (pred = predname->pred)->nclause) {
@@ -342,8 +342,14 @@ int main(int argc, char **argv) {
 			exit(1);
 		}
 		prg->meta_release = pred->clauses[0]->params[0]->value;
-	} else if(need_meta) {
-		report(LVL_WARN, 0, "No release number declared.");
+		if(pred->nclause > 1) {
+			report(LVL_WARN, pred->clauses[0]->line, "%d separate definitions found for (story release $). Only the first (at this line) will be used.", pred->nclause);
+		}
+	} else {
+		if(need_meta) {
+			report(LVL_WARN, 0, "No release number declared.");
+		}
+		prg->meta_release = 1;
 	}
 	
 	if(serial_overridden) {
diff --git a/src/frontend.c b/src/frontend.c
index 1e2a7e90..c2461685 100644
--- a/src/frontend.c
+++ b/src/frontend.c
@@ -2399,26 +2399,42 @@ static void assign_select_statements(struct program *prg) {
 	selectforms = 0;
 }
 
-char *decode_metadata_str(int builtin, struct word *param, struct program *prg, struct arena *arena) {
+char *decode_metadata_str(int builtin, struct word *param, struct program *prg, struct arena *arena, const char *report_as, int lib_file) {
 	struct predname *predname;
 	struct predicate *pred;
-	char *buf;
+	char *buf = 0;
 	int i;
+	int nfound = 0;
+	int nlib = 0;
+	line_t whichline = 0;
 
 	predname = find_builtin(prg, builtin);
 	pred = predname->pred;
 	for(i = 0; i < pred->nclause; i++) {
 		if(!param
 		|| (pred->clauses[i]->params[0]->kind == AN_DICTWORD && pred->clauses[i]->params[0]->word == param)) {
-			if(decode_output(&buf, pred->clauses[i]->body, 0, 0, arena, "Story metadata")) {
-				return buf;
-			} else {
-				return 0;
+			if(!nfound) { // First one found
+				if(!decode_output(&buf, pred->clauses[i]->body, 0, 0, arena, "Story metadata")) {
+					buf = 0; // Failed to decode into buf
+				}
+				whichline = pred->clauses[i]->line;
+			}
+			nfound ++;
+			if(FILENUMPART(pred->clauses[i]->line) == lib_file) { // This one was in a library file
+				nlib ++;
 			}
 		}
 	}
 
-	return 0;
+	if(nfound - nlib > 1) {
+		if(param) {
+			report(LVL_WARN, whichline, "%d separate definitions found for (%s @%s) outside of the library. Only the first (at this line) will be used.", nfound, report_as, param->name);
+		} else {
+			report(LVL_WARN, whichline, "%d separate definitions found for (%s) outside of the library. Only the first (at this line) will be used.", nfound, report_as);
+		}
+	}
+
+	return buf;
 }
 
 int frontend(struct program *prg, int nfile, char **fname, dictmap_callback_t dictmap_callback) {
@@ -2482,6 +2498,7 @@ int frontend(struct program *prg, int nfile, char **fname, dictmap_callback_t di
 	} else if(lexer.lib_file != nfile - 1) {
 		report(LVL_WARN, 0, "The library (in this case %s) should normally appear last on the commandline.", sourcefile[lexer.lib_file]);
 	}
+	prg->lib_file = lexer.lib_file;
 	
 	// Warn about objects never used as topics, depending on topic_warning_level
 	if(prg->topic_warning_level == WARN_DEFAULT && lexer.lib_file >= 0) { // Default: warn only if library file found
@@ -2896,7 +2913,7 @@ int frontend(struct program *prg, int nfile, char **fname, dictmap_callback_t di
 
 	for(i = 0; i < prg->nboxclass; i++) {
 		struct boxclass *bc = &prg->boxclasses[i];
-		char *css = decode_metadata_str(BI_STYLEDEF, bc->class, prg, &lexer.temp_arena);
+		char *css = decode_metadata_str(BI_STYLEDEF, bc->class, prg, &lexer.temp_arena, "style class", lexer.lib_file);
 		char *param, *str;
 		struct boxclassline *bcl, **bclptr;
 
diff --git a/src/frontend.h b/src/frontend.h
index 3843a824..90dd23e4 100644
--- a/src/frontend.h
+++ b/src/frontend.h
@@ -16,7 +16,7 @@ int body_succeeds(struct astnode *an);
 int body_might_stop(struct astnode *an);
 int body_succeeds_at_most_once(struct astnode *an);
 void frontend_add_builtins(struct program *prg);
-char *decode_metadata_str(int builtin, struct word *param, struct program *prg, struct arena *arena);
+char *decode_metadata_str(int builtin, struct word *param, struct program *prg, struct arena *arena, const char *report_as, int lib_file);
 int frontend(struct program *prg, int nfile, char **fname, dictmap_callback_t dictmap_callback);
 int frontend_inject_query(struct program *prg, struct predname *predname, struct predname *tailpred, struct word *prompt, const uint8_t *str);