> ## Documentation Index
> Fetch the complete documentation index at: https://base-a060aa97-roethke-b20-upgrade-pages.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# IActivationRegistry Reference

> Generated B20 reference for IActivationRegistry functions, events, and errors.

## Functions

| Function | Selector | Summary |
| - | - | - |
| [`isActivated`](/specifications/b20/reference/interfaces/i-activation-registry/is-activated) | `0xba87af80` | Whether `feature` is currently activated. Never reverts. |
| [`checkActivated`](/specifications/b20/reference/interfaces/i-activation-registry/check-activated) | `0xde5bfd9b` | Reverts with `FeatureNotActivated(feature)` if `feature` is not currently activated. |
| [`admin`](/specifications/b20/reference/interfaces/i-activation-registry/admin) | `0xf851a440` | The address authorized to call `activate` and `deactivate`. |
| [`activate`](/specifications/b20/reference/interfaces/i-activation-registry/activate) | `0x59db6e85` | Activates `feature`. Emits `FeatureActivated`. |
| [`deactivate`](/specifications/b20/reference/interfaces/i-activation-registry/deactivate) | `0x22eee84c` | Deactivates `feature`. Emits `FeatureDeactivated`. |

## Events

| Event | Topic0 | Summary |
| - | - | - |
| `FeatureActivated` | `0x8c7a0ecdbb8d96e867e43ec1aef80027976ee493c18bef399fa799ed19752451` | Emitted when `feature` is activated. |
| `FeatureDeactivated` | `0x15bf65a782c3258c63268ba9d7aed710cf9f9315d3687d9a4632ccdad7926c84` | Emitted when `feature` is deactivated. |

## Errors

| Error | Selector | Summary |
| - | - | - |
| `Unauthorized` | `0x8e4a23d6` | Caller is not the activation admin. |
| `AlreadyActivated` | `0x866b0041` | Feature is already activated. |
| `FeatureNotActivated` | `0xb9b2a425` | Feature is not activated. |
| `DelegateCallNotAllowed` | `0x0d89438e` | The precompile was invoked via `DELEGATECALL` or `CALLCODE`. |
| `StaticCallNotAllowed` | `0xbeaba5b7` | A state-mutating entry point was invoked from a `STATICCALL` frame. |