Model versions and lifecycle

Each Vertex AI Generative AI language model is available in a stable version and a latest version. The language models include text and code models, such as text-bison, chat-bison, code-bison, and code-gecko. The versions differ by whether they change over time or not and by how long they're available.

Stable version

A stable version of a model does not change and is available for six months after the release date of its subsequent version. For example, text-bison@001 is available for six months after the release date of text-bison@002. In this example, text-bison@001 becomes unavailable after the six months following the release date of text-bison@002. If you use a stable version that becomes unavailable, you need to switch to a newer available stable version. You can identify the version of a stable model by the three digit number that's appended to the model name. For example, text-bison@001 is version number one of the stable release of the Vertex AI Generative AI text model.

Google releases stable versions on a regular cadence. You can switch from one stable version to another as long as the other version is still available. When you move from one stable version to a different stable version, you need to run your tuning jobs again because there might be prompt, output, and other differences between the versions.

Available stable model versions

The following stable model versions are available for generally available Generative AI models:

chat-bison model Release date
chat-bison@001 July 10, 2023
code-bison model Release date
code-bison@001 June 29, 2023
codechat-bison model Release date
codechat-bison@001 June 29, 2023
code-gecko model Release date
code-gecko@001 June 29, 2023
text-bison model Release date
text-bison@001 June 7, 2023
textembedding-gecko model Release date
textembedding-gecko@001 June 7, 2023

Latest version

The latest version of a model is updated periodically and includes incremental updates and improvements. These changes might result in subtle differences in the output over time for a given prompt. The latest model is declared stable after a cycle of testing and review. To specify the latest name of a model, provide the model name without the version number. For example, the name of the latest version of the text chat model is chat-bison.

The latest version of a model is not guaranteed to be production ready. To specify a stable release of a model, include the model version. For example, text-bison@001.

Latest models

The following are the latest available Generative AI model versions:

text-bison models text-bison
chat-bison models chat-bison
code-bison models code-bison
codechat-bison models codechat-bison
code-gecko models code-gecko
textembedding-gecko models textembedding-gecko

How to specify the version of a language model

To use the stable version of a language model, append the three digit version number to the model. For example, to specify the stable text-bison model that's version six, append @006 to the model's name:

To use the latest version of a model, don't append anything to the model name. For example, the following uses the latest version of the codechat-bison model:

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