db-schema/db_scripts/base/4042.down

DELETE FROM provisioning.voip_preferences WHERE internal = -1;

ALTER TABLE provisioning.voip_preferences DROP COLUMN `read_only`;
ALTER TABLE provisioning.voip_preferences DROP COLUMN `description`;
ALTER TABLE provisioning.voip_preferences MODIFY COLUMN `internal` bool NOT NULL default FALSE;
ALTER TABLE provisioning.voip_preferences MODIFY COLUMN `data_type` enum('bool','int','string') NOT NULL default 'string';

UPDATE provisioning.voip_preferences SET data_type = 'bool' where data_type = '';