Date: 1811
From: Rabbi Moshe Sofer
To: Unknown recipient
The Chasam Sofer rules that dina d'malchusa dina applies to currency changes enacted for the king's legitimate governmental interests, obligating debtors to repay in the new currency. A borrower who repeatedly delayed payment until the currency was invalidated bears the resulting loss. The Rema's notation of dissent is limited to arbitrary royal decrees unrelated to the king's financial interest.
Source: Shu"t Chasam Sofer CM §58