Let’s just say OpenAI has been having some…trouble making easy-to-find official announcements for things.
According to other plugin developers, they received an email directly telling them to migrate their plugins into a custom GPT. This info is also found scattered around other docs and blurbs when they discuss GPTs.
Thanks. I did a deep dive into GPTs vs Plugins last week. Most of the top developers have already created (switched?) to GPTs. The only “official” announcement I could find was this: ChatGPT Plugins waitlist