Hi.
Version 1.3 was vault format 6.
Latest is vault format 8
So, updating from 1.3 to 1.17 means 2 vault updates.
Between 1.3 and 1.4, the installation id was changed, which might cause issues. (Edit: sorry, only on windows. So I guess the following workaround is not needed)
I would do a backup of my settings ([Win 10] One issue discovered with 1.4.15 [Updated] - #6 by overheadhunter) and the vault.
And then uninstall the 1.3 version, install the latest version.
Restore the settings and open the vault. Then the migration process of the vault format should start.
I don’t think that old iPad apps can open newer vaults. How should they recognize formats designed in the future. So you’ll have to update you iPad app as well. I also wonder in that case why you would stick to an outdated app for your sensitive files?