The @farfetch/blackout-core package has been split in 3 different packages now: @farfetch/blackout-client, @farfetch/blackout-analytics and @farfetch/blackout-redux.
If you were using client modules from @farfetch/blackout-core/*/client, check the migration file for @farfetch/blackout-client to know how you can upgrade to the @farfetch/blackout-client package and use its corresponding modules.
If you were using analytics modules from @farfetch/blackout-core/analytics, check the migration file for @farfetch/blackout-analytics to know how you can upgrade to the @farfetch/blackout-analytics package and use its corresponding modules.
If you were using redux modules from @farfetch/blackout-core/*/redux or using some utils like buildListingHash, check the migration file for @farfetch/blackout-redux to know how you can upgrade to the @farfetch/blackout-redux package and use its corresponding modules.