diff --git a/index.bs b/index.bs
index f896612..964fc4b 100644
--- a/index.bs
+++ b/index.bs
@@ -554,6 +554,8 @@ For this sample group entry, the grouping_type_parameter syntax is
metadata_specific_parameters provides an additional part of the grouping_type_parameter, which MAY be used to distinguish different sample groups having the same metadata_type but different sub-parameters. In this version of the specification, metadata_specific_parameters is only defined when metadata_type is set to METADATA_TYPE_ITUT_T35 in which case its value SHALL be set to the first 24 bits of the metadata_itut_t35 structure. For other types of metadata, its value SHOULD be set to 0. In all cases, when the grouping_type_parameter is used, readers processing sample groups SHALL use the entire value of grouping_type_parameter.
+NOTE: The current design is constrained to using only 3 bytes for ITU-T T.35 identification, which typically suffices for the itu_t_t35_country_code and the itu_t_t35_terminal_provider_code identification. Consequently, inspection of the payload becomes essential if an implementation aims to determine the values of subsequent bytes, for instance, the itu_t_t35_terminal_provider_oriented_code.
+
CMAF AV1 track format {#cmaf}
=====================================================
@@ -708,4 +710,5 @@ Changes since v1.2.0 release {#changelist}
- Update the CMAF section to mention the cmf2 brand.
- Clarify the color info in the codecs string.
- Make assert-id's unique and add them to the previous version.
+- Add a note on the identification of the T.35 message.
- Use undated reference for ISOBMFF.