This is a historical overview of GPT-4 and the GPT-4o and GPT-4.5 developments discussed in 2023–2025. It is not a list of the latest models or a recommendation that these versions remain available. Check the provider’s current catalogue and deprecation notices before choosing a deployment.
What GPT-4 introduced to this discussion
GPT-4 is a language-model family used for tasks such as drafting, summarising, answering questions and working with code. ChatGPT is a product through which different models may be offered; “ChatGPT-4” is not a precise identifier for every configuration. A useful evaluation records the actual model and tools used.
Generated text can be fluent while containing factual errors, unsupported references or insecure code. Performance depends on the task, instructions, available context and deployment. A larger model does not remove the need for verification.
GPT-4o and GPT-4.5 in historical context
GPT-4o broadened the discussion around multimodal interaction. Text, image and audio capabilities must be checked against the specific product and endpoint: a model announcement does not mean every modality is available in every interface.
GPT-4.5 was a research preview introduced in 2025, with capabilities and a lifecycle distinct from GPT-4o. It should not be described as a dedicated reasoning model simply because it can produce multistep answers. Product access, pricing and lifecycle can change independently of the historical launch.
Cybersecurity implications
Potential uses include helping draft policies, summarise logs or explain code. These outputs need review by someone who understands the underlying evidence. Do not treat a generated finding as a verified vulnerability or a generated answer as an authorisation to test a system.
Before connecting organisational data or tools, review confidentiality, retention, permissions and third-party terms. Limit tool access, validate proposed actions and test how untrusted documents affect the workflow. Multimodal inputs add data types to assess rather than a guarantee of better security.
How to read this archive
Use this article to understand the historical model family. For a current selection, define the task, test a specific supported model and check lifecycle notices. Avoid carrying old prices, context limits or availability assumptions into a new project.
Official references: GPT-4, GPT-4o, GPT-4.5 and deprecation notices. Editorial review: 30 October 2026.
