Here's my recommended update for the description:

```
#### iOS Tab Icons

On iOS, tab icons are usually white with a transparent background. The system uses a transparent tint color to indicate whether the tab is active or inactive. In the inactive state, the tint color is based on the tab bar's color [tabsBackgroundColor](Titanium.UI.TabGroup.tabsBackgroundColor), which defaults to black. In the active state, the tint color is usually blue. Prior to Titanium 3.1, there was no way to override the default active icon tint.

Titanium 3.1 introduced some new ways to customize tab icons, which are supported in iOS 5.0 and above:

*   You can specify the active tab's tint color as [activeTabIconTint](Titanium.UI.TabGroup.activeTabIconTint).

*   You can set separate icon images for the active and inactive states. If [activeIcon](Titanium.UI.Tab.activeIcon) is set, then `icon` is used in the inactive state, and `activeIcon` is used in the active state. **No default tint is applied to either icon.**
```