Navis has made structural changes to certain forms for N4 versions 2.2 and above. If you have overridden any of these forms using the database-backed variform override functionality, you will need to perform specific upgrade actions in order for these forms to work.
The following changes make upgrade actions for database-backed variforms necessary:
With each release, Navis is converting selected forms and tables in N4 to be platform neutral. This requires a change to the XML for that form. Therefore, when Navis makes a form or table platform neutral, any existing database-backed variform override to that form or table will not work without an upgrade action.
Actions: Before the upgrade, export your database-backed variforms to a temporary location. Immediately after the upgrade, you must reapply your database-backed variform changes to the new platform-neutral form or table. Note that the XML syntax for the platform-neutral form is different from the syntax used in your original variform override. See Maintain variform customizations after upgrades with converted platform-neutral forms (on page 1).
Starting in N4 2.2, database-backed variforms use an .xsd schema instead of .dtd. Additionally, starting in N4 2.2, you can select a scope for each of your database-backed variforms. Therefore, if you are upgrading from a version below 2.2, and if your terminal has overridden any system variforms, or if you have created custom variforms, you must convert them to use the new .xsd schema. This means the database table config_variform should not contain any records that use .dtd as the schema.
Action: Immediately after the upgrade, you must change the header lines in all of your overridden variforms to refer to the .xsd schema. For instructions, see Convert .dtd variform overrides to .xml variform overrides (on page 1).