"update" to cyrus 2.2.10 with MacOS X 10.3.9. Server?

I was just reading about the 10.3.9 update for MacOS X Server. Apple states:

"- update to Cyrus version 2.2.10 for more reliable email message storage"

I thought 10.3.8 with all security updates had 2.2.12. Is this one less reliable than 2.2.10? Any comments?

Thanks, Pascal