[Shotwell] Problem upgrading 0.6.1 to 0.20.1

[Supermanduriano <supermanduriano gmail com>]

Dear all,

I have recently upgraded my oldstable Debian (squeeze) to stable
(Jessie) and with it, I upgraded shotwell from 0.6.1 to 0.20.1.

I have years of work on building my photo database and I wanted to
transfer it to the new version, so I just backuped and copied photo.db
in the new location.

When I run shotwell 0.20.1, this error message appears:

ERROR:src/db/DatabaseTable.c:1269:database_table_add_column: assertion
failed: (res == Sqlite.OK)
Aborted

I was wondering if there is a way to fix the database or a tool to
convert it from older versions. I would be gutted to lose all the work I
did to build the database.

Thank you for your help,
Manduriano