MS-DOS batch that works in W2k and up - but not Win95

I have this batch working magnificantly in Windows 2000 and 2003 and XP with the help of the Experts here; but not in Win95!  What do I need to change in order to make this batch work under Win95, and, determine which OS it is running under and work accordingly?  I will never use anything older that Win95.

I suspect it is the for statements?

@echo off
setlocal

CD \RMS\C001\DL
COPY C:\GEMCOM\BACKUP\01VERIFO.DAT C:\RMS\C001\DL\01VERIFO.DAT
COPY C:\RMS\C001\DR\DRSA* C:\RMS\C001\DL\DRSA*

for /f "tokens=1,* delims==" %%a in ('type "C:\PDIMSG32\PDIMSG32.PMC" 2^>NUL') do if /i "%%a"=="Storeid" set locvar=%%b&goto FOUNDIT

echo NO store ID !!
pause
goto :EOF

:FOUNDIT
for /F "tokens=1-4 delims=/- " %%a in ('date/T') do set date=%%d%%c%%b
for /F "tokens=1-4 delims=/- " %%a in ('date/T') do set /a DAY=%%b

set /a YESTERDAY = DATE - 100

if  "%DAY%" == "1" (
     set YESTERDAY=%DATE%
)else (
     set YESTERDAY = DATE - 100
)

set drdate=%yesterday:~6,2%%yesterday:~4,2%
set locvar=%locvar:~-3%
echo %locvar%
echo %drdate%

for /f "delims=" %%a in ('dir /b /a-d DRSA*.') do call :PROCESS "%%a"
goto :EOF
:PROCESS
set FileName=%~nx1
rename "%FileName%" "%locvar%%drdate%.P%FileName:~4%"
:EOF