> ## Documentation Index
> Fetch the complete documentation index at: https://docs.abbyy.com/llms.txt
> Use this file to discover all available pages before exploring further.

# FREngineVersionEnum

FREngineVersionEnum enumeration constants are used to denote previously supported versions of ABBYY FineReader Engine.

```
typedef enum {
 FREV_10,
 FREV_11
} FREngineVersionEnum;
```

## Elements

| Name       | Description                                                   |
| ---------- | ------------------------------------------------------------- |
| FREV\\\_10 | The major supported version of ABBYY FineReader Engine is 10. |
| FREV\\\_11 | The major supported version of ABBYY FineReader Engine is 11. |

## Used in

[FRDocument::ConvertFromOldVersion](/fine-reader/engine/api-reference/document-related-objects/frdocument/convertfromoldversion-method)