From: Rabbi Moshe Sofer
To: Rabbi Pinchas Leib Munk
The Chasam Sofer analyzes the katlanis restriction for a twice-widowed woman whom his student was considering marrying, examining the Rambam-Rosh dispute, the leniencies of the Terumos HaDeshen, and the mitigating factor of old age. Without issuing a definitive heter, he advises the student to investigate whether the first husband had reached the age of seventy before proceeding, and offers only a cautious blessing if the student chooses to marry on his own initiative.
Source: Shu"t Chasam Sofer EH I §23