diff --git a/lib/content_encoding.c b/lib/content_encoding.c
index b724b576b4..f128f7565f 100644
--- a/lib/content_encoding.c
+++ b/lib/content_encoding.c
@@ -384,12 +384,10 @@ static CURLcode brotli_map_error(BrotliDecoderErrorCode be)
   case BROTLI_DECODER_ERROR_FORMAT_WINDOW_BITS:
   case BROTLI_DECODER_ERROR_FORMAT_PADDING_1:
   case BROTLI_DECODER_ERROR_FORMAT_PADDING_2:
-#ifdef BROTLI_DECODER_ERROR_COMPOUND_DICTIONARY
+#ifdef BROTLI_DECODER_ERROR_COMPOUND_DICTIONARY  /* brotli v1.1.0+ */
   case BROTLI_DECODER_ERROR_COMPOUND_DICTIONARY:
 #endif
-#ifdef BROTLI_DECODER_ERROR_DICTIONARY_NOT_SET
   case BROTLI_DECODER_ERROR_DICTIONARY_NOT_SET:
-#endif
   case BROTLI_DECODER_ERROR_INVALID_ARGUMENTS:
     return CURLE_BAD_CONTENT_ENCODING;
   case BROTLI_DECODER_ERROR_ALLOC_CONTEXT_MODES: