Duruud hama!
I'm currently looking at the conjugation of Classical Persian, lingua franca of the old Persianate Islamic world, which was brought into the Indian subcontinent by Turkic Muslims and became influential there for centuries. Searching has not yielded much for me yet, since all the learning material online goes over the modern language. Though, I have been able to gather these pieces of information regarding the older language (some of these may be incorrect):
(using transliterations as I'm no good with Arabic script)
Subjunctive mood was (mostly) merged with indicative (outside of budan), didn't use today's be- prefix (used for other purposes then, including perfective aspect)
Imperfective aspect was not prefixed with mi- at the time, instead usually suffixed with -i (also doubled as past conditional)
Remnant optative -ad (sometimes plural -adand), now obsolete outside budan, still existed (the infamous "murdabad" loanword involves the optative of budan)
Passive voice in light verbs retained kardan before shodan
Progressive aspect used istadan after verb (still preserved in Tajik) instead of dastan before verb
Although I've found these few useful tidbits, I still don't have a full picture. Any works I can look at which go into Classical Persian conjugation in much more detail? Or a chart which I can compare with modern conjugation? Sipas.