Note OpenAI calls models that are no longer available for usage 'deprecated,' while Anthropic reserves that term for models that are only available for existing users and uses the term 'retired' for models that are no longer available in any capacity. From a legal standpoint, the training of AI models on copyrighted content continues to be a point of contention, and some models are more prone to leaking or regurgitating content verbatim, which prompts their hurried retirement.