Sitefinity 12 project trying to load a reference that I've already removed

I've just upgraded my Sitefinity project to version 12.0.7000. It works locally without issue however when I deploy it to my dev environment, I get this error while it's trying to update:

Could not load file or assembly 'Telerik.Sitefinity.Frontend.SocialShare, Version=10.2.6625.0, Culture=neutral, PublicKeyToken=b28c218413bdf563' or one of its dependencies. The located assembly's manifest definition does not match the assembly reference. (Exception from HRESULT: 0x80131040)

Since the social widget was deprecated in version 11.1, I have already removed any references to social sharing (as per the documentation) long ago. I have even deployed to dev with version 11.2.6xxx without issue.

Also, when I run it locally, I'm using the same database as what's in my dev environment.

I've search my solution for any kind of reference to socialshare and have found nothing.

I've tried the following:

https://knowledgebase.progress.com/articles/Article/Social-share-DLL-s-causing-issue-while-upgrade

https://knowledgebase.progress.com/articles/Article/Pages-that-have-Social-Sharing-widgets-on-them-throw-an-exception-after-upgrade-to-Sitefinity-11-1

Turns out the deploy process through Octopus was not removing additional files so the old files were being left in there. I changed the setting in Octopus to this:

Remove Additional Files: Files int eh destination that are not part of the deployment will be removed.

Duh. o_O