Index: src/OFString+JSONValue.m
==================================================================
--- src/OFString+JSONValue.m
+++ src/OFString+JSONValue.m
@@ -135,10 +135,13 @@
 			ret |= c + 10 - 'A';
 		else
 			return 0xFFFF;
 	}
 
+	if (ret == 0)
+		return 0xFFFF;
+
 	return ret;
 }
 
 static inline OFString*
 parseString(const char *restrict *pointer, const char *stop,

Index: src/ObjFW.h
==================================================================
--- src/ObjFW.h
+++ src/ObjFW.h
@@ -131,10 +131,11 @@
 #endif
 #import "OFTruncatedDataException.h"
 #import "OFUnboundNamespaceException.h"
 #import "OFUnlockFailedException.h"
 #import "OFUnsupportedProtocolException.h"
+#import "OFUnsupportedVersionException.h"
 #import "OFWriteFailedException.h"
 
 #import "macros.h"
 
 #ifdef OF_HAVE_PLUGINS