Julian Date and Mail script

Hello there
Some help is needed with the below script. When I run the script, the “current date” &“/” &“msgNo” advances the message number.
The problem is when I save the script as an application, and then open the application, the message number does not advance each time I open the application.
On my previous MacBookPro, I had this script saved on the top tool bar; however, I have forgotten how I managed to get the script on the tool bar.
Any advice would be appreciated.
Regards
Jeffrey

property lastDate : ""
property lastMsgNo : 0

set jDay to do shell script "date +%j"
set jYear to do shell script "date +%y"
set theSubject to jYear & jDay & "/"

set theYEar to do shell script "date +%y" -- two digit year
set theMonth to do shell script "date +%m" -- two digit month
set theMonth2 to (do shell script "date +%B" & " | tr \"[:lower:]\" \"[:upper:]\"")
set theDay to do shell script "date +%d" -- two digit day of month
set theHour to do shell script "date +%H" -- two digit hour (24 hour clock)
set theMinute to do shell script "date +%M" -- two digit minute
set theSecond to do shell script "date +%S" -- two digit second


-- convert the month2 name to a 3 char name
set theMonth2 to characters 1 thru 3 of theMonth2 as string

set currentDate to do shell script "date +%y%j"

if lastDate = "" then -- i.e. first run of script
	set lastDate to jYear & jDay
	
end if

if lastDate = currentDate then
	set lastMsgNo to lastMsgNo + 1
else
	set lastMsgNo to 1
	set lastDate to currentDate
end if

set msgNo to text -2 thru -1 of (("00" & lastMsgNo) as string) -- make 2 digit number

set theSubject to currentDate & "/" & msgNo

set theBody to "DE VJNK NR " & jYear & jDay & "/" & msgNo & return ¬
	& "R " & theDay & theHour & theMinute & "Z " & theMonth2 & theYEar & return ¬
	& "FM KENDAL JN" & return ¬
	& "TO" & return ¬
	& "BT" & return ¬
	& "UNCLAS" & return & return ¬
	& "BT" & return & return & return & return & return & return & return & return ¬
	& "NNNN"

tell application "Mail"
	activate
	set theNewMessage to make new outgoing message with properties {subject:theSubject, content:theBody}
	tell theNewMessage to set visible to true
	-- Default is false. Determines whether the compose window will
	-- show on the screen or whether it will happen in the background.
end tell

([applescript] and [/applescript] code posting tags added by NG.)

What version of macOS are you running? App properties don’t persist under macOS 11.0 and above.

Hello Shane
I am using OS 12.0.1 (Monterey).
Is there a fix/work-around?
Regards
Jeffrey

To remember the state of a variable between launches of an application or a script, property list files are used. Although, you can memorize it in a plain text file. You should each time read this variable from this file, then save it back when variable’s value changes.

You can use my PrefsStorageLib, available here:

https://latenightsw.com/freeware/

When properties stopped working for me, I began using text files to save persistent values. This is easily done and reasonably quick.

When I began using ASObjC, I started using plists to store persistent values. The following saves and returns a list.

use framework "Foundation"
use scripting additions

-- set plist location and name
set preferencesFolder to POSIX path of (path to preferences)
set settingPlist to preferencesFolder & "JulianDateAndMailSetting.plist" -- set to whatever is desired

-- remove comment from following line to write plist
-- writePlist(settingPlist, {1, (current date)}) --> true

-- remove comment from following line to read plist
-- set theSettings to readPlist(settingPlist) --> {1, date "Monday, November 15, 2021 at 9:06:17 AM"}

on readPlist(thePath)
	set theArray to current application's NSArray's arrayWithContentsOfFile:thePath
	return theArray as list
end readPlist

on writePlist(thePath, theList)
	set theArray to current application's NSArray's arrayWithArray:theList
	theArray's writeToFile:thePath atomically:true
end writePlist