[Yaffs] Upgrading from a very old revision

Hi,

I am considering to upgrade yaffs for an embedded system. That system is
currently running linux 2.6.19 with a yaffs code from a revision dated
of August 2008.
The compilation of the system with an updated yaffs code went very well,
and early tests showed that the system started.
Is there any reason to worry about a possible incompatibility that may
trigger later because some infrequently used files are still stored with
the data format in place 4 years ago ?

Thank you.