If you are a BlackBerry Enterprise Administrator you often manage a wide range of devices with different firmware versions so that it is very hard to rollout a software which is build for a specified OS. BUT you can create a *.alx file (in my case a sametime.alx) which can be used to install different software versions depending on the OS.

The key for this is the "_blackberryVersion" (case sensitive) you can find more infos in the BlackBerry Developer Guide but for Sametime 8.5 you can use this file here (click on read more...):

<loader version="1.0">
<application id="Sametime">
<name>Sametime</name>
<description>Sametime Mobile 8.5</description>
<version>8.5</version>
<vendor>IBM Lotus Software</vendor>
<copyright>Copyright (c) 2008 IBM Lotus Software</copyright>
<!-- CODs with OS-specific code. Must never be installed on BlackBerrys running an OS version lower than the target OS. -->
<!--A system_independent app only gets replaced during an OS update if the OS contains a later version -->
<!-- This File was created by Bastian Wieczorek -->
<apptype>system_independent</apptype>
<fileset Java="1.25" _blackberryVersion="[4.7,4.8)">
<!-- Add here the Sametime folder and files for the 4.7 OS -->
<directory>4.7</directory>
<files>
Sametime.cod
Sametime-1.cod
Sametime-2.cod
Sametime-3.cod
Sametime-4.cod
Sametime-5.cod
</files>
</fileset>
<fileset Java="1.25" _blackberryVersion="[4.6,4.7)">
<!-- Add here the Sametime folder and files for the 4.6 OS -->
<directory>4.6</directory>
<files>
Sametime.cod
Sametime-1.cod
Sametime-2.cod
Sametime-3.cod
Sametime-4.cod
Sametime-5.cod
</files>
</fileset>
<fileset Java="1.25" _blackberryVersion="[4.5,4.6)">
<!-- Add here the Sametime folder and files for the 4.5 OS -->
<directory>4.5</directory>
<files>
Sametime.cod
Sametime-1.cod
Sametime-2.cod
Sametime-3.cod
Sametime-4.cod
Sametime-5.cod
</files>
</fileset>
<fileset Java="1.25" _blackberryVersion="[4.2,4.3)">
<!-- Add here the Sametime folder and files for the 4.2 OS -->
<directory>4.2</directory>
<files>
Sametime.cod
Sametime-1.cod
Sametime-2.cod
Sametime-3.cod
Sametime-4.cod
Sametime-5.cod
</files>
</fileset>
<fileset Java="1.25" _blackberryVersion="[4.1,4.2)">
<!-- Add here the Sametime folder and files for the 4.1 OS -->
<directory>4.1</directory>
<files>
Sametime.cod
Sametime-1.cod
Sametime-2.cod
Sametime-3.cod
Sametime-4.cod
Sametime-5.cod
Sametime-6.cod
</files>
</fileset>
</application>
</loader>