[CentOS] Updates in same major version number ?

Fri May 30 21:54:44 UTC 2008
Emmanuel Fournier <fournier at ict-toulouse.asso.fr>

May be already asked, sorry so !

But what is the best method when updating between
4.4 and 4.5
4.4 and 4.6
5.0 and 5.1

Is it ok to update only with 'yum update' cmd, with no risk ?

Thanks you for your support,
Emmanuel Fournier - ICT