Yes, 2.5x version do not support unicode.
I know only about examples that shipped with SW2.51, and custom scripts already written. What is your target?
If you saved file several times, you can try to use some kind of file restore utility. Last time I was in trouble, Recuva helped me. https://www.lifewire.com/free-data-recovery-software-tools-2622893
Wow, great news!
Delete subtitle (only from translation http://subtitry.ru/feedback/index.php?showtopic=2123 Insert subtitle (only in translation) http://subtitry.ru/feedback/index.php?showtopic=2122
Load Turkish subs as original, load English subs like translation, swap (there is option in menu), save English texts with Turkish timings.
http://subtitry.ru/feedback/index.php?showtopic=2113
http://subtitry.ru/feedback/index.php?showtopic=2113