Mhum ok, but how ? in entitie .yml / .xml ?
Beacause in tools interface, when start new project :
File > Create project > New ORM Project > Doctrine2 ORM > Symfony3
And add "update_at" field with "datetime" I can't find somting "On Update Gedmo" in interface ;(
If i need to use export, add this " * @Gedmo\Timestampable(on="update")" in the file and import, it is so mhum... not user freindly...