> ## 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.

# Upgrading ABBYY FineReader Engine library

> Upgrade the ABBYY FineReader Engine library on Windows to a newer version without uninstalling — applies to Release 5+ for Developer installation and Release 6+ for Runtime.

<Note>
  This topic applies to FRE for Windows.
</Note>

Starting with Release 5 of ABBYY FineReader Engine, you will be able to upgrade to newer versions without uninstalling the product first. Simply run the installer in the same way.

The following conditions apply:

* For Developer installation, the version already installed is no older than Release 5.
* For Runtime installation, the version already installed is no older than Release 6.
* The build number of the version you are going to install is newer than the one already installed in the first three numbers:
  * 12.5.12.0 -> 12.5.15.0 — OK
  * 12.5.12.0 -> 12.6.1.0 — OK
  * 12.5.12.0 -> 13.1.1.0 — OK
  * 12.5.12.0 -> 12.5.12.1 — NOT OK, only the fourth number is newer
  * 12.5.12.0 -> 12.5.11.0 — NOT OK, already installed version is newer

If you are upgrading from version older than Release 5 (Release 6 for Runtime), or the build number conditions aren't fulfilled, you will have to uninstall ABBYY FineReader Engine and then install the new version, as before.