Revayats

The Revayats (also spelled as Rivayats) are a series of exchanges between the Zoroastrian community in India and their co-religionists in early modern Iran. They have been ascribed the same importance of the Talmud to Judaism by Jivanji Jamshedji Modi.
The word Revayat has disputed etymology. Some claim the word to have origins from Arabic but this is contentious.
Overview.
The content of each Revayat varies but they are usually queries on matters of worship, customs, rituals and observance. The issues range form the mundane, such as queries about the preparation of ink for the writing of religious documents, to important issues including conversion.
Over three centuries, twenty-two Revayats were sent from India to Persia. The first Revayat was brought in 1478 AD by Nariman Hoshang of Broach. Hoshang was a layman, supported by Chang Asa a notable leader of the Navsari Parsi community. Hoshang spent a year in Yazd, learning Persian and supported himself by 'petty trade'. Eventually his Persian improved to the extent that he was able to question the dasturs of Iran.
After this initial Revayat, Indian priests would gather up questions and send representatives to Iran with the questions. These Revayats are known by the emissary who brought them back. Some Revayats are anonymous as the person who brought them is unknown, these Rivatays are more or less incomplete.
In the 17th Century the Revayats were classified according to the subject they pertained to by Hormazdyar Framarz, Darab Hormazdyar, and Barzo Kamdin.
The Revayats are notable as the only Modern Persian text composed in the Avestan script.
During the 18th Century the Kadmi sects in both Iran and India exchanged additional Revayats, which culminated in the Revayat-e Haftad va Hast (translated as the Revayat of 78 Questions) (also known as the Ithoter Revayat).