TS stability - which is the best version?

[Adam Hardy <adam.ts@xxxxxxxxxxxxxxxxxx>]

I'm using TS4.0 build 23, running on WinNT4 client - the original configuration 
more or less, just a few upgrades like a new harddrive etc.
I used to be very happy until recently that this was a very stable configuration 
that met all my needs.
However the EL system I am working on now is big, almost to the limit that I 
have to clean up unused variables and remove lines I don't need anymore, 
otherwise I hit the maximum size limit.
That would be fine since I don't want this system to get any more complicated, 
but TS4 chart scanner has become badly unreliable and crashes out every 1 in 10 
or perhaps 1 in 5 runs.
Does anyone recall whether TS4 became more reliable post Y2K (the last time I 
upgraded)? Is there a definitive 'best' version of TS?
Thanks
Adam