migrating from 4 to 5 and no database usable

[Luca Ferrari]

Hi all,
due to the explosion of my old computer I update digikam from the last
4 branch to the new 5.3 one as of kubuntu 16.10.
I've got all my stuff in digikam4.db (fully backupped for God sake!),
but when I start digikam 5.3 it is unable to find/migrate the
database.
A little inspecting points me to the fact it is trying to use mysql
(something I would like to avoid):

digikam.general: AlbumWatch use QFileSystemWatcher
digikam.general: Database Parameters:
   Type:                     ""
   DB Core Name:             ""
   DB Thumbs Name:           ""
   DB Face Name:             ""
   Connect Options:          ""
   Host Name:                ""
   Host port:                -1
   Internal Server:          false
   Internal Server Path:     "/home/luca/.local/share/digikam/"
   Internal Server Serv Cmd: "mysqld"
   Internal Server Init Cmd: "mysql_install_db"
   Username:                 ""
   Password:                 ""

QSqlDatabase:  driver not loaded
QSqlDatabase: available drivers: QSQLITE QMYSQL QMYSQL3 SKGSQLCIPHER
digikam.dbengine: Error while opening the database. Error details [
QSqlError("", "Driver not loaded", "Driver not loaded") ]
digikam.dbengine: Error while opening the database. Error details [
QSqlError("", "Driver not loaded", "Driver not loaded") ]
digikam.dbengine: Error while opening the database. Error details [
QSqlError("", "Driver not loaded", "Driver not loaded") ]
digikam.dbengine: Error while opening the database. Error details [
QSqlError("", "Driver not loaded", "Driver not loaded") ]
digikam.dbengine: Error while opening the database. Error details [
QSqlError("", "Driver not loaded", "Driver not loaded") ]


Now, if I go the settings and try to configure digikam to poin to the
sqlite3 digikam4.db it refuses to accept the setting (not allowing me
to press the OK button).
Am I missing some package?

Thanks,
Luca