Percona Server 5.5 to 5.6 In-Place upgrade

Hi !
I want upgrade Percona Server 5.5.40 to last 5.6, i was read manual provided on site https://www.percona.com/doc/percona-server/5.6/upgrading_guide_55_56.html

It contain links to MySQL manual, which alert about TIMESTAMP incompatibility. Does upgrade procedure need any additional steps except provided in manual or mysql_upgrade is enough to resolve all issues with 5.5 -> 5.6 upgrade ?

Thank you