In PSP34 the Transfer event possesses field "from" that is unnecessary.
One can always deduce the previous owner of a token with an ID based on the previous Transfer event that contains the ID.
If such a previous event doesn't exist it means that the token hasn't been minted.
I would recommend changing the standard. Changes to events will not break the cross-contract calls. Also If one assumes the new standard in one's off-chain application the application will be compatible with the previous standard as long as one allows the field "from" to be undefined.
In PSP34 the Transfer event possesses field "from" that is unnecessary.
One can always deduce the previous owner of a token with an ID based on the previous Transfer event that contains the ID.
If such a previous event doesn't exist it means that the token hasn't been minted.
I would recommend changing the standard. Changes to events will not break the cross-contract calls. Also If one assumes the new standard in one's off-chain application the application will be compatible with the previous standard as long as one allows the field "from" to be undefined.