When Invoiceplane is upgraded from 1.6.1 to 1.6.2 (beta 2) the database migration is causing an error and migration can't be continued.

Expected Behavior

Database migration should be successful

Current Behavior

Database migration is causing an error and ip is broken

Screenshots

Possible Solution

When table is deleted manually, the migration can be continued, but this should not be the recommended solution. This should be fixed in the migration script somehow.

Steps to Reproduce

1. Replace old (1.6.1) files with new (1.6.2) files
2. Go to /index.php/setup/upgrade_tables
3. Click through the migration wizard