To apply this change on existing on existing table:
ALTER TABLE stock MODIFY order_id BIGINT UNSIGNED

Before, when creating new full inventory Document, resources which are not
present in new Inventory Document were simply ignored. So, new movements were
added "manually" with quantity less than or equal to 0 to workaround this
issue.

New inventory fixes this issue so that this workaround is not needed
anymore. Temporary movements are created for resources not present in new
Inventory Document and added to stock table (through z_catalog_stock_list Z
SQL Method) with uid equals to Inventory Document UID.  However, the primary
key on stock table is (uid BIGINT UNSIGNED, order_id TINYINT UNSIGNED), thus
when there are strictly more than 255 temporary movements, order_id overflows
because the max value of TINYINT UNSIGNED is 255 and MySQL sets order_id to
255 after the first 255 temporary movements (as strict SQL mode is not
enabled), thus raising an IntegrityError later on because of duplicated
entries.