Pa.multilingual LRF -> DexterityContainers

Plone Support Administering Plone sites
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1

Hi,
I migrate an old site to 4.3-latest with plone.app.multilingual (2.0.3), on startup following warning shows up:

DeprecationWarning: LanguageRootFolder: LanguageRootFolders should be migrate to DexterityContainers from plone.app.multilingual.content.lrf import LanguageRootFolder

Aren't plone.app.multilingual LRF Dexterity container?

Or where does this Upgrade-Step happens?

Current 4.3.4.1 with pam 2.0.1 says nothing about DexterityContainers...