Question on the requirements for Slack V2 Next Generation migration

Hi,

The Slack V2 Next Gen migration guide says the first requirement before the migration is:

In order to configure the Slack V2 Next Generation update, you must complete the Slack webhook migration first

What is “Slack webhook migration” that the requirement is referring to? Does it mean to say generic webhook migration (v1 & v2 to v3)?

Thanks.