Ironclad 2.0 introduced a new database format. Your old database files won't work with new versions of Ironclad but you can upgrade them easily using the instructions below.

First, export the entries from your old database using any 1.x version of Ironclad (you can find all previous releases of Ironclad on the releases page):

$ ironclad export > passwords.json

Next, create a new database using the latest 2.x version of Ironclad.

$ ironclad init new-database.idb

Finally, import the entries into the new database:

$ ironclad import passwords.json

Be sure to securely delete the passwords.json file when you're done as it contains your exported passwords in plaintext.