Example of a batch file that can start APPX and automatically update the 
APPX/Client to the most recent version prior to logon:

rem  AppxJAVA.bat
rem  Batch file to launch Appx Java Client and keep it updated.
xcopy x:\Appx\StartUp\Images\splash.jpg c:\"Program Files"\AppxClient\
                        themes\default\ /d
xcopy x:\Appx\StartUp\login.ini c:\"Program Files"\AppxClient\ /d
xcopy x:\Appx\StartUp\JavaClientUpdate\AppxClient.exe c:\"Program Files"\
                        AppxClient\ /d
xcopy x:\Appx\StartUp\JavaClientUpdate\Appx.jar c:\"Program Files"\
                        AppxClient\ /d

"C:\Program Files\AppxClient\AppxClient.exe" -cols=80 -rows=25
                 -title="Appx -$(user) on $(host):$(port), PID $(pid)
exit

The following batch file does the same for the Appx Windows Client.

rem AppxWin3.bat
rem 09/03/99 PAK
rem
rem Batch file ran on each client at startup of Appx
rem i.e., the Appx Desktop shortcut should point to this file
rem
rem XCOPY switches:
rem /d - Copies only those files whose source time is newer than
rem      the destination file.
rem /i - If destination does not exist and copying more than one file,
rem      assumes that the destination must be a directory.
rem /u - Copies only files that already exist in destination
rem
rem Copies the Latest Version of Appx to your computer!
rem
xcopy x:\appx\appx.exe c:\Appx\Win32\ /d

md c:\Appx\Win32\data
xcopy x:\appx\startup\winprint.exe c:\Appx\Win32\data\ /d

rem for WinNT, HOSTS file is in: Winnt\system32\drivers\etc\
xcopy x:\Appx\Startup\Hosts.* c:\Winnt\system32\drivers\etc\ /d /i
xcopy x:\Appx\Startup\Hosts   c:\Winnt\system32\drivers\etc\ /d
start c:\Appx\Win32\Appx.exe -c