: Multiple versions of the RTE can coexist on one machine. If you have applications built with different LabVIEW versions (e.g., 8.2 and 8.5.1), you must install both corresponding RTE versions.

: It includes a web browser plug-in that enables users to view and interact with Virtual Instruments (VIs) embedded in web pages via Remote Front Panels .

Released during the Windows Vista era, this version has specific legacy OS requirements: LabVIEW - NI Forums

: The engine is designed to be multilingual, supporting various localized versions of applications. Critical Compatibility Rules

The is a critical software component for anyone needing to run stand-alone executables or shared libraries (DLLs) created with National Instruments (NI) LabVIEW 8.5.1 .

: On 64-bit systems, you can install 32-bit and 64-bit versions of the same RTE version side-by-side. System Requirements for Version 8.5.1

The LabVIEW RTE provides the necessary libraries and support routines required for LabVIEW-built applications to function.

Maintaining compatibility is the most common reason users seek out this specific version.

: LabVIEW executables are version-specific. An application built in LabVIEW 8.5.1 requires the 8.5.1 Run-Time Engine .