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Now that we identified some Signals to react upon, we can start implementing Slots for these signals. For the first Signal, which is issued as soon as a new version of Content is published, there exists a method in eZ\Publish\SPI\Persistence\Content\UrlAlias\Handler for exactly that purpose: publishUrlAliasForLocation(). The Signal contains the ID of the content object item and its newly published version number. Using this information, the corresponding Slot can fulfill its purposes with the following steps:
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