# 9. Glossary

This page includes definitions for various common FMOD Studio terms, along with references to related terms and documentation.

## 9.1 Documentation Conventions

### 9.1.1 Parameter Tokens

Token | Meaning
--- | ---
Out | The API function will fill in information in this parameter.
Opt | This parameter is optional, specify null or zero to ignore.
R/O | This token applies to members of various structures which FMOD passes to user callbacks. User callbacks must not modify the values of these members. Modifying the values of these members will cause undefined behavior.
C# | This is only available in C#.
JS | This is only available in Javascript.

## 9.2 Version

The version number of FMOD Studio. Version numbers are split into three parts, in the format: productVersion.majorVersion.minorVersion. For example, the version 1.23.45 would indicate product version 1, major version 23, and minor version 45 of that major version.

Major versions contain significant changes, add new features, and may affect bank compatibility. Updating to a new major version usually requires project migration. New major versions may change playback behavior in some cases.

Minor versions, also known as patch versions, contain bug fixes and smaller workflow improvements.